All 400 quiz questions in 10 units, with the correct answer and an explanation for each. Read a unit, then test yourself in the Senior 2 quiz.
1.A systematic error is an error that:
Answer: B
Systematic errors, such as a zero error, push all readings the same way; averaging does not remove them.
2.A ruler whose end is worn away gives readings that are always too large. This is an example of:
Answer: D
The error is the same for every reading, so it is a systematic zero error.
3.Random errors in an experiment can best be reduced by:
Answer: B
Random errors scatter readings both ways, so averaging many readings reduces their effect.
4.Parallax error happens when:
Answer: C
Reading a scale from an angle makes the pointer appear against the wrong mark; the eye must be perpendicular to the scale.
5.Which action helps avoid parallax error when reading a measuring cylinder?
Answer: A
The eye should be level with the bottom of the meniscus (for water) to avoid parallax.
6.A vernier caliper reads 0.02 cm when its jaws are closed. A measured reading is 3.46 cm. What is the corrected length?
Answer: A
A positive zero error is subtracted: 3.46 − 0.02 = 3.44 cm.
7.The smallest division on a metre rule is 1 mm. A reasonable uncertainty in a single reading is:
Answer: B
The uncertainty is usually taken as half of the smallest division, ± 0.5 mm.
8.A length is measured as (20.0 ± 0.5) cm. What is the percentage uncertainty?
Answer: D
Percentage uncertainty = (0.5 ÷ 20.0) × 100 = 2.5 %.
9.The range of a measurement written as (12.4 ± 0.2) s is:
Answer: C
Subtract and add the uncertainty: 12.4 − 0.2 = 12.2 s and 12.4 + 0.2 = 12.6 s.
10.How many significant figures are in 0.00450?
Answer: A
Leading zeros are not significant; the 4, 5 and the trailing zero after the decimal point are, giving 3.
11.How many significant figures are in 2006?
Answer: B
Zeros between non-zero digits are significant, so 2006 has 4 significant figures.
12.How many significant figures are in 3.20 × 10⁴?
Answer: D
In scientific notation all digits shown in 3.20 are significant: 3.
13.Round 4.6758 to three significant figures.
Answer: C
The fourth figure is 5, so the third figure (7) rounds up to 8: 4.68.
14.Round 0.07349 to two significant figures.
Answer: D
The first two significant figures are 7 and 3; the next digit is 4, so we round down: 0.073.
15.Round 1846 to two significant figures.
Answer: B
The third figure is 4, so we round down and keep the place value: 1800.
16.A student calculates 12.5 × 3.1. Written to the correct number of significant figures, the answer is:
Answer: C
The answer should have as many significant figures as the least precise value (3.1 has 2), so 38.75 becomes 39.
17.The accuracy of a measurement describes:
Answer: C
Accuracy is closeness to the true value; precision is how close repeated readings are to each other.
18.Readings 5.21 cm, 5.22 cm and 5.21 cm are close together but the true value is 5.40 cm. These readings are:
Answer: A
The readings agree closely (precise) but are far from the true value (not accurate), suggesting a systematic error.
19.Which instrument is most suitable for measuring the diameter of a thin wire?
Answer: B
A micrometer screw gauge reads to 0.01 mm, suitable for very small diameters.
20.Five readings of a time are 2.1 s, 2.3 s, 2.2 s, 2.0 s and 2.4 s. What is the mean?
Answer: C
Mean = (2.1 + 2.3 + 2.2 + 2.0 + 2.4) ÷ 5 = 11.0 ÷ 5 = 2.2 s.
21.To measure the period of a pendulum more accurately, a student should:
Answer: C
Timing many oscillations reduces the effect of reaction-time error on each period.
22.Which of the following is a source of error caused by the observer?
Answer: A
Parallax error comes from the observer's eye position; the others come from the instrument or environment.
23.Write 0.000 52 m in standard form.
Answer: D
Move the decimal point 4 places to the right: 5.2 × 10⁻⁴ m.
24.The absolute error of a measurement is:
Answer: B
Absolute error = |measured value − true value|, in the same unit as the measurement.
25.A length is measured as 9.6 cm but the true value is 10.0 cm. What is the absolute error?
Answer: B
Absolute error = |9.6 − 10.0| = 0.4 cm.
26.For the same measurement (9.6 cm, true value 10.0 cm), what is the percentage error?
Answer: A
Percentage error = 0.4 ÷ 10.0 × 100 = 4 %.
27.Relative error is calculated as:
Answer: A
Relative error has no unit; multiply by 100 to get percentage error.
28.Two lengths (10.0 ± 0.2) cm and (5.0 ± 0.1) cm are added. The result is:
Answer: A
When quantities are added, their absolute uncertainties add: 0.2 + 0.1 = 0.3 cm.
29.(20.0 ± 0.3) cm − (8.0 ± 0.2) cm gives:
Answer: D
In subtraction the absolute uncertainties still add: 0.3 + 0.2 = 0.5 cm.
30.A card is (4.0 ± 0.1) cm long and (2.0 ± 0.1) cm wide. What is its area with uncertainty?
Answer: D
Relative uncertainties add: 0.1/4.0 + 0.1/2.0 = 0.075; 0.075 × 8.0 = 0.6 cm².
31.Systematic errors can be removed by taking many readings and averaging them.
Answer: False
Averaging reduces random errors only; systematic errors must be removed by correcting the instrument or method.
32.Leading zeros, such as those in 0.0034, are not significant figures.
Answer: True
Leading zeros only show the position of the decimal point.
33.Reading a scale with the eye directly above the mark helps avoid parallax error.
Answer: True
Viewing perpendicular to the scale lines up the eye, pointer and mark.
34.Precision describes how close a measurement is to the true value.
Answer: False
That is accuracy; precision describes how close repeated measurements are to each other.
35.When two measured quantities are added or subtracted, their absolute uncertainties are added.
Answer: True
Uncertainties never cancel; they always combine.
36.An error that makes all readings too large or too small by the same amount is called a ______ error.
Answer: systematic
Systematic errors shift every reading in the same direction.
37.The error caused by viewing a scale at an angle is called ______ error.
Answer: parallax
The eye must be directly in line with the mark to avoid it.
38.The number 0.0607 has ______ significant figures.
Answer: 3 (three)
The 6, the zero between 6 and 7, and the 7 are significant.
39.An instrument that does not read zero when nothing is being measured has a ______ error.
Answer: zero
A zero error must be added or subtracted from every reading.
40.The uncertainty in a result calculated from several measured quantities is called a ______ error.
Answer: compound
Each measured quantity contributes to the final uncertainty.
1.Linear motion is motion:
Answer: D
Linear (rectilinear) motion takes place along a straight line.
2.Uniform velocity means that an object:
Answer: D
Uniform velocity means constant speed in a constant direction.
3.Acceleration is defined as:
Answer: C
a = (v − u)/t, the rate of change of velocity, in m/s².
4.A car accelerates uniformly from 0 to 20 m/s in 5 s. What is its acceleration?
Answer: B
a = (v − u)/t = (20 − 0)/5 = 4 m/s².
5.Which equation correctly gives the final velocity of a body moving with uniform acceleration?
Answer: B
From a = (v − u)/t, rearranging gives v = u + at.
6.A body starts from rest and accelerates at 3 m/s² for 4 s. What is its final velocity?
Answer: B
v = u + at = 0 + 3 × 4 = 12 m/s.
7.Which equation gives the displacement of a uniformly accelerating body in terms of u, a and t?
Answer: C
The second equation of motion is s = ut + ½at².
8.A ball starts from rest and accelerates at 2 m/s² for 5 s. How far does it travel?
Answer: D
s = ut + ½at² = 0 + ½ × 2 × 5² = 25 m.
9.Which equation does NOT contain time?
Answer: C
v² = u² + 2as links velocities, acceleration and displacement without time.
10.A car moving at 10 m/s accelerates at 2 m/s² over 24 m. What is its final velocity?
Answer: D
v² = u² + 2as = 100 + 2 × 2 × 24 = 196, so v = 14 m/s.
11.A bus moving at 20 m/s brakes to rest in 4 s. What is its deceleration?
Answer: B
a = (0 − 20)/4 = −5 m/s², a deceleration of 5 m/s².
12.Using the bus above (20 m/s to rest in 4 s), how far does it travel while braking?
Answer: B
s = ½(u + v)t = ½(20 + 0) × 4 = 40 m.
13.On a velocity–time graph, the gradient (slope) represents:
Answer: A
Gradient = change in velocity ÷ time = acceleration.
14.On a velocity–time graph, the area under the line represents:
Answer: C
Area = velocity × time = displacement.
15.On a displacement–time graph, a straight sloping line shows:
Answer: D
A constant gradient on an s–t graph means constant velocity.
16.A horizontal line on a velocity–time graph shows that the body:
Answer: B
Velocity does not change, so acceleration is zero and velocity is constant.
17.A free-falling body near the Earth's surface (no air resistance) has an acceleration of about:
Answer: C
The acceleration due to gravity, g, is about 9.8 m/s² (often taken as 10 m/s²).
18.In free fall without air resistance, a heavy stone and a light stone dropped together:
Answer: A
All bodies fall with the same acceleration g when air resistance is negligible.
19.A stone is dropped from rest and falls for 3 s. Taking g = 10 m/s², what is its speed?
Answer: B
v = u + gt = 0 + 10 × 3 = 30 m/s.
20.A stone is dropped from rest and falls for 3 s (g = 10 m/s²). How far does it fall?
Answer: A
s = ½gt² = ½ × 10 × 3² = 45 m.
21.A ball is thrown vertically upwards at 20 m/s (g = 10 m/s²). How long does it take to reach its highest point?
Answer: A
At the top v = 0: 0 = 20 − 10t, so t = 2 s.
22.For the ball thrown upwards at 20 m/s (g = 10 m/s²), what maximum height does it reach?
Answer: B
v² = u² − 2gh: 0 = 400 − 20h, so h = 20 m.
23.At the highest point of its flight, a ball thrown vertically upward has:
Answer: A
Its velocity is momentarily zero, but gravity still accelerates it downwards at g.
24.Displacement differs from distance because displacement:
Answer: D
Displacement is a vector (magnitude and direction); distance is a scalar.
25.A runner goes 100 m east and then 40 m west. What is the displacement?
Answer: A
Displacement = 100 − 40 = 60 m in the east direction.
26.A car travels 120 km in 2 hours. What is its average speed in m/s?
Answer: C
60 km/h = 60 000 m ÷ 3600 s ≈ 16.7 m/s.
27.A motorcycle accelerates from 5 m/s to 25 m/s in 4 s. How far does it travel in this time?
Answer: C
s = ½(u + v)t = ½(5 + 25) × 4 = 60 m.
28.Uniformly accelerated rectilinear motion is motion in a straight line with:
Answer: A
Velocity changes by equal amounts in equal times along a straight line.
29.A car speeds up uniformly from rest to 20 m/s in 10 s. Using the area under its velocity–time graph, how far does it travel?
Answer: D
Area of the triangle = ½ × 10 × 20 = 100 m.
30.A stone dropped from rest falls 80 m to the ground (g = 10 m/s²). How long does it take?
Answer: A
s = ½gt²: 80 = 5t², so t² = 16 and t = 4 s.
31.The area under a velocity–time graph gives the distance travelled.
Answer: True
Area = velocity × time = displacement.
32.A body moving with constant velocity has a non-zero acceleration.
Answer: False
Constant velocity means velocity does not change, so acceleration is zero.
33.Without air resistance, all objects near the Earth fall with the same acceleration.
Answer: True
This acceleration is g ≈ 9.8 m/s², independent of mass.
34.Deceleration means that the velocity of a body is decreasing.
Answer: True
Deceleration is negative acceleration: the body slows down.
35.For uniformly accelerated motion, the velocity–time graph is a straight line.
Answer: True
A constant gradient means constant acceleration.
36.The rate of change of velocity is called ______.
Answer: acceleration
Acceleration is measured in m/s².
37.The SI unit of acceleration is ______.
Answer: m/s² (metre per second squared)
Velocity (m/s) divided by time (s).
38.The gradient of a displacement–time graph gives the ______.
Answer: velocity
Gradient = displacement ÷ time.
39.Motion of a body falling under gravity alone is called free ______.
Answer: fall
In free fall the only force is the body's weight.
40.The equation v² = u² + 2as does not contain ______.
Answer: time (t)
It links u, v, a and s only.
1.Friction is a force that:
Answer: B
Friction acts along the surfaces in contact and opposes relative motion or attempted motion.
2.Friction is mainly caused by:
Answer: B
Even smooth-looking surfaces have tiny bumps that interlock and resist sliding.
3.Static friction acts when:
Answer: A
Static friction prevents motion from starting, up to a maximum (limiting) value.
4.Kinetic (sliding) friction acts when:
Answer: B
Kinetic friction acts on surfaces sliding over each other.
5.Compared with sliding friction, rolling friction is usually:
Answer: A
Rolling causes much less resistance, which is why wheels and ball bearings are used.
6.Limiting friction is:
Answer: B
Limiting friction is the largest friction force before slipping begins.
7.Which law of solid friction is correct?
Answer: C
Friction F = μR, so it is proportional to the normal reaction R and independent of contact area.
8.The coefficient of friction μ is defined as:
Answer: B
μ = frictional force ÷ normal reaction; it has no unit.
9.A 20 N box rests on a floor where μ = 0.4. What is the limiting friction?
Answer: C
On a level floor R = weight = 20 N, so F = μR = 0.4 × 20 = 8 N.
10.A force of 12 N just starts a 40 N block moving on a level table. What is the coefficient of static friction?
Answer: D
μ = F ÷ R = 12 ÷ 40 = 0.3.
11.The coefficient of friction has:
Answer: D
It is a ratio of two forces, so it has no unit.
12.Which of the following is an advantage of friction?
Answer: A
Friction between shoes and the ground lets us push off and walk.
13.Which of the following is a disadvantage of friction?
Answer: D
Friction wears away moving parts and wastes energy as heat.
14.Which is a method of reducing friction?
Answer: C
Lubricants separate the surfaces with a thin layer, reducing friction.
15.Ball bearings reduce friction because they:
Answer: B
Rolling friction is much smaller than sliding friction.
16.Car tyres have treads mainly to:
Answer: D
Treads push water away and keep good friction between tyre and road.
17.Streamlining a car or aeroplane is done to reduce:
Answer: A
A smooth, tapered shape lets air flow past with less resistance.
18.Which force is the upward push of a surface on an object resting on it?
Answer: A
The normal reaction acts perpendicular to the surface.
19.Air resistance on a falling object increases as:
Answer: A
Drag increases with speed until it balances the weight at terminal velocity.
20.When the air resistance on a falling parachutist equals her weight, she:
Answer: B
With no resultant force, her velocity stays constant: terminal velocity.
21.A box is pushed with 30 N across a floor and the friction is 18 N. What is the resultant force?
Answer: D
Resultant = 30 − 18 = 12 N in the direction of the push.
22.A 5 kg box is pulled with 25 N against a friction of 10 N. What is its acceleration?
Answer: B
Resultant = 25 − 10 = 15 N; a = F/m = 15 ÷ 5 = 3 m/s².
23.Brake pads in a bicycle slow it down by:
Answer: A
The pads rub on the rim or disc, and friction converts kinetic energy to heat.
24.Rubbing your hands together makes them warm because:
Answer: C
Work done against friction is converted to thermal energy.
25.Which pair of surfaces would have the LEAST friction?
Answer: C
Smooth, hard, slippery surfaces like ice and polished steel have very low friction.
26.Increasing the weight of a box sliding on a floor will:
Answer: D
A heavier box increases the normal reaction, and friction is proportional to it.
27.The friction force between two solid surfaces depends mainly on:
Answer: D
Rougher surfaces and larger normal forces give more friction.
28.Friction that acts on objects moving through liquids or gases is called:
Answer: A
Air resistance and water resistance are forms of fluid friction.
29.Athletes wear spiked shoes in order to:
Answer: C
Spikes dig into the track and stop the feet slipping.
30.A meteor glows as it enters the Earth's atmosphere because:
Answer: C
Friction with the air converts kinetic energy into heat and light.
31.Frictional force depends on the area of contact between two solid surfaces.
Answer: False
By the laws of solid friction, friction is independent of contact area.
32.Rolling friction is generally smaller than sliding friction.
Answer: True
That is why wheels and bearings make motion easier.
33.Lubricants increase friction between moving parts.
Answer: False
Lubricants reduce friction by keeping surfaces apart.
34.Friction always acts in the direction opposite to the relative motion or attempted motion.
Answer: True
Friction opposes sliding between the surfaces.
35.Without friction, it would be easy to walk on a smooth floor.
Answer: False
Without friction our feet would slip; friction is needed to walk.
36.The ratio of frictional force to normal reaction is called the coefficient of ______.
Answer: friction
μ = F ÷ R.
37.Friction between surfaces that are sliding over each other is called ______ friction.
Answer: kinetic (sliding/dynamic)
It acts on surfaces in relative motion.
38.Oil and grease used to reduce friction are called ______.
Answer: lubricants
They form a thin layer between surfaces.
39.The maximum static friction just before motion starts is called ______ friction.
Answer: limiting
Beyond this value, the body starts to slide.
40.The constant velocity reached when air resistance balances weight is called ______ velocity.
Answer: terminal
At terminal velocity the resultant force is zero.
1.Pressure is defined as:
Answer: D
P = F/A, the force acting normally on each unit of area.
2.The SI unit of pressure is the:
Answer: B
1 Pa = 1 N/m².
3.A force of 50 N acts on an area of 0.25 m². What is the pressure?
Answer: B
P = F/A = 50 ÷ 0.25 = 200 Pa.
4.A box of weight 600 N rests on a face of area 1.5 m². What pressure does it exert on the floor?
Answer: A
P = 600 ÷ 1.5 = 400 Pa.
5.The same brick is placed on the floor in three ways. It exerts the greatest pressure when resting on:
Answer: D
The weight is the same, so the smallest area gives the greatest pressure.
6.Why do knives cut better when they are sharp?
Answer: A
For the same force, a tiny edge area gives a very high pressure.
7.Why do tractors and tanks have wide tracks?
Answer: C
A larger area lowers the pressure, so the vehicle does not sink.
8.The pressure at a depth h in a liquid of density ρ is given by:
Answer: B
Liquid pressure P = hρg (depth × density × g).
9.Find the water pressure at a depth of 5 m (ρ = 1000 kg/m³, g = 10 m/s²).
Answer: A
P = hρg = 5 × 1000 × 10 = 50 000 Pa.
10.Pressure in a liquid at rest:
Answer: B
At any point in a fluid at rest, pressure acts equally in all directions.
11.Water spurts furthest from the lowest hole in a tall tin because:
Answer: D
The deepest hole has the greatest water pressure behind it.
12.The walls of a dam are built thicker at the bottom because:
Answer: D
Pressure increases with depth, so the base must withstand the greatest force.
13.Liquid pressure at a given depth does NOT depend on:
Answer: C
P = hρg contains no term for the container's shape.
14.Which liquid gives the greatest pressure at a depth of 10 cm?
Answer: A
At the same depth, the densest liquid gives the greatest pressure.
15.A diver goes from 2 m to 12 m deep in water (ρ = 1000 kg/m³, g = 10 m/s²). By how much does the water pressure increase?
Answer: D
Increase = Δh ρ g = 10 × 1000 × 10 = 100 000 Pa.
16.A manometer is an instrument used to measure:
Answer: B
A manometer compares a gas pressure with another pressure, often atmospheric pressure.
17.When a gas supply is connected to one arm of a manometer, the liquid in that arm goes down. This means the gas pressure is:
Answer: C
The gas pushes the liquid down on its side, so its pressure is greater.
18.The difference in levels in a water manometer is 20 cm. What is the excess pressure of the gas? (ρ = 1000 kg/m³, g = 10 m/s²)
Answer: C
ΔP = hρg = 0.20 × 1000 × 10 = 2000 Pa.
19.Mercury is used instead of water in manometers that measure large pressures because mercury:
Answer: A
Mercury's high density gives a short, manageable column for large pressures.
20.In a liquid at rest, all points at the same horizontal level are at:
Answer: A
In a continuous liquid at rest, pressure depends only on depth.
21.A liquid 'finds its own level' in connected vessels of different shapes because:
Answer: D
Equilibrium requires equal pressure at equal depths, so the surfaces are level.
22.Pascal's principle states that pressure applied to an enclosed fluid:
Answer: B
A change in pressure in a confined fluid is transmitted undiminished throughout it.
23.Which device works on Pascal's principle?
Answer: C
Hydraulic machines use pressure transmitted through a liquid.
24.Liquids are used in hydraulic machines mainly because liquids are:
Answer: D
Liquids hardly compress, so pressure is transmitted fully.
25.In a hydraulic lift, F₁/A₁ = F₂/A₂. A 50 N force on a 2 cm² piston lifts a load on a 200 cm² piston. What is the load?
Answer: A
F₂ = F₁ × A₂/A₁ = 50 × 200/2 = 5000 N.
26.Hydraulic brakes in a car work because:
Answer: B
The pedal's piston pressurises the fluid, which pushes the brake pistons at each wheel.
27.The instrument used to measure atmospheric pressure is a:
Answer: C
Barometers measure atmospheric pressure.
28.In a simple mercury barometer, the height of the mercury column at sea level is about:
Answer: A
Atmospheric pressure supports about 760 mm (76 cm) of mercury.
29.Oil and water are poured into the same beaker. The oil forms a layer on top because:
Answer: B
Non-miscible liquids form layers, with the denser liquid at the bottom.
30.In a U-tube, a 10 cm column of oil balances an 8 cm column of water above their common level. What is the density of the oil? (water = 1000 kg/m³)
Answer: C
h₁ρ₁ = h₂ρ₂: 10 × ρ = 8 × 1000, so ρ = 800 kg/m³.
31.For the same force, a smaller area produces a larger pressure.
Answer: True
P = F/A, so pressure increases as area decreases.
32.Pressure in a liquid decreases with depth.
Answer: False
Liquid pressure increases with depth: P = hρg.
33.The pressure at the bottom of a liquid depends on the shape of the container.
Answer: False
Pressure depends only on depth, density and g.
34.Pascal's principle states that pressure applied to an enclosed fluid is transmitted equally in all directions.
Answer: True
This is the statement of Pascal's principle.
35.A hydraulic press multiplies both force and energy.
Answer: False
It multiplies force, but energy (work) cannot be multiplied.
36.Force acting normally per unit area is called ______.
Answer: pressure
P = F/A, in pascals.
37.The pressure at depth h in a liquid of density ρ is P = ______.
Answer: hρg
Depth × density × gravitational field strength.
38.A U-tube containing liquid used to measure gas pressure is called a ______.
Answer: manometer
It compares the gas pressure with atmospheric pressure.
39.The principle that pressure in an enclosed fluid is transmitted equally to all parts is called ______'s principle.
Answer: Pascal
Named after Blaise Pascal.
40.The instrument used to measure atmospheric pressure is called a ______.
Answer: barometer
Mercury and aneroid barometers are common types.
1.A simple machine is a device that:
Answer: B
Machines let a small effort move a large load.
2.The force applied to a machine is called the:
Answer: A
The effort is the input force.
3.The force overcome by a machine is called the:
Answer: A
The load is the output force.
4.Mechanical advantage (MA) of a machine is:
Answer: D
MA tells how many times the machine multiplies the effort.
5.A machine lifts a load of 600 N with an effort of 150 N. What is its MA?
Answer: B
MA = 600 ÷ 150 = 4.
6.Velocity ratio (VR) of a machine is:
Answer: C
VR depends only on the design of the machine.
7.In a machine the effort moves 5 m while the load moves 1 m. What is the VR?
Answer: C
VR = 5 ÷ 1 = 5.
8.Efficiency of a machine is given by:
Answer: D
Efficiency = MA/VR × 100 % = work output/work input × 100 %.
9.A machine has MA = 3 and VR = 4. What is its efficiency?
Answer: D
Efficiency = 3 ÷ 4 × 100 = 75 %.
10.The efficiency of a real machine is always less than 100 % because of:
Answer: A
Some input work is wasted.
11.A lever is a rigid bar that turns about a fixed point called the:
Answer: B
The fulcrum is the pivot point.
12.In a first-class lever, the fulcrum is:
Answer: B
Examples: see-saw, crowbar, pair of scissors.
13.A wheelbarrow is a lever of which class?
Answer: C
The wheel is the fulcrum, the load is in the middle and the effort at the handles.
14.In a third-class lever, such as tweezers or the human forearm, the:
Answer: C
Third-class levers have MA less than 1 but increase distance moved.
15.Which is a first-class lever?
Answer: B
The pivot of a see-saw is in the middle.
16.The principle of moments states that, for a balanced lever:
Answer: B
Moment = force × perpendicular distance from the pivot.
17.A load of 200 N is 0.5 m from the fulcrum of a lever. What effort 2 m from the fulcrum balances it?
Answer: D
Effort × 2 = 200 × 0.5, so effort = 50 N.
18.A single fixed pulley:
Answer: C
It lets you pull down to lift a load up.
19.A single movable pulley has a velocity ratio of:
Answer: D
Two rope sections support the load.
20.In a pulley system, the VR is equal to:
Answer: A
Each supporting section shares the load.
21.An inclined plane (ramp) makes it easier to:
Answer: A
Pushing up a slope needs less force than lifting vertically.
22.A ramp 6 m long rises 1.5 m. What is its velocity ratio?
Answer: A
VR = length ÷ height = 6 ÷ 1.5 = 4.
23.A screw is an example of:
Answer: C
The thread is a spiral inclined plane.
24.A wheel and axle, such as a screwdriver handle, multiplies force because:
Answer: B
VR = radius of wheel ÷ radius of axle.
25.A wheel of radius 30 cm turns an axle of radius 5 cm. What is the VR?
Answer: B
VR = 30 ÷ 5 = 6.
26.Gears are used in bicycles to:
Answer: D
Different gear sizes give different speeds and forces.
27.Oiling the moving parts of a machine increases its:
Answer: C
Less friction means less energy wasted.
28.A machine with MA less than 1, such as a pair of tweezers, is useful because it:
Answer: D
Not all machines multiply force; some give speed or precision.
29.A crowbar is used to lift a heavy stone. The crowbar acts as a:
Answer: A
It turns about a pivot to multiply the effort.
30.A pulley system with 4 supporting rope sections lifts a load of 800 N with an effort of 250 N. What is its efficiency?
Answer: A
MA = 800 ÷ 250 = 3.2; VR = 4; efficiency = 3.2 ÷ 4 × 100 = 80 %.
31.A machine can produce more work than is put into it.
Answer: False
Work output is always less than or equal to work input.
32.A see-saw is an example of a first-class lever.
Answer: True
The fulcrum is between the effort and the load.
33.A single fixed pulley has a velocity ratio of 2.
Answer: False
A single fixed pulley has VR = 1; it only changes direction.
34.Efficiency = (MA ÷ VR) × 100 %.
Answer: True
This is the efficiency of a machine.
35.An inclined plane lets a smaller force raise a load, but over a longer distance.
Answer: True
This is the trade-off in all machines.
36.The fixed point about which a lever turns is called the ______.
Answer: fulcrum (pivot)
Levers are classified by its position.
37.Load ÷ effort gives the ______ advantage of a machine.
Answer: mechanical
MA = L/E.
38.Distance moved by effort ÷ distance moved by load gives the velocity ______.
Answer: ratio
VR depends on the machine's design.
39.A sloping surface used to raise loads with less force is called an ______ plane.
Answer: inclined
Ramps are inclined planes.
40.The moment of a force = force × perpendicular ______ from the pivot.
Answer: distance
Measured in N m.
1.An isolated system is one that:
Answer: D
In an isolated system the total energy stays constant.
2.An open system is one that:
Answer: B
A boiling pot without a lid is an open system.
3.Kinetic energy is the energy a body has because of its:
Answer: C
Any moving body has kinetic energy.
4.The formula for kinetic energy is:
Answer: A
KE = ½mv², in joules.
5.What is the kinetic energy of a 2 kg ball moving at 3 m/s?
Answer: A
KE = ½ × 2 × 3² = 9 J.
6.If the speed of a car doubles, its kinetic energy becomes:
Answer: D
KE ∝ v², so doubling v multiplies KE by 4.
7.Gravitational potential energy is the energy a body has because of its:
Answer: B
PE = mgh depends on height.
8.What is the potential energy of a 4 kg object 5 m above the ground? (g = 10 m/s²)
Answer: D
PE = mgh = 4 × 10 × 5 = 200 J.
9.Mechanical energy of a body is:
Answer: D
Mechanical energy = KE + PE.
10.In an isolated system with no friction, the total mechanical energy:
Answer: D
KE and PE change into each other, but their sum is conserved.
11.A ball is dropped from a height. As it falls (no air resistance):
Answer: A
Potential energy is converted into kinetic energy.
12.A 2 kg stone is dropped from 20 m (g = 10 m/s²). What is its kinetic energy just before hitting the ground?
Answer: B
KE gained = PE lost = mgh = 2 × 10 × 20 = 400 J.
13.Using v = √(2gh), find the speed of an object that falls 5 m from rest (g = 10 m/s²).
Answer: A
v = √(2 × 10 × 5) = √100 = 10 m/s.
14.The speed at which a falling object hits the ground (no air resistance) depends on:
Answer: B
From mgh = ½mv², v = √(2gh); mass cancels.
15.At the highest point of a swing of a pendulum, the bob has:
Answer: A
It is momentarily at rest at the top, so all its energy is potential.
16.At the lowest point of its swing, a pendulum bob has:
Answer: C
PE is lowest there, so KE and speed are greatest.
17.A pendulum bob is released from 0.2 m above its lowest point (g = 10 m/s²). What is its speed at the bottom?
Answer: A
v = √(2gh) = √(2 × 10 × 0.2) = √4 = 2 m/s.
18.A ball is thrown upwards at 10 m/s (g = 10 m/s²). How high does it rise?
Answer: B
½mv² = mgh gives h = v²/2g = 100 ÷ 20 = 5 m.
19.A pendulum eventually stops swinging because:
Answer: A
The system is not isolated; energy is transferred to the surroundings as heat.
20.A roller coaster car is at rest at the top of a 45 m hill (g = 10 m/s², no friction). What is its speed at the bottom?
Answer: C
v = √(2gh) = √(2 × 10 × 45) = √900 = 30 m/s.
21.A 0.5 kg ball has 25 J of kinetic energy. What is its speed?
Answer: B
v = √(2KE/m) = √(2 × 25 ÷ 0.5) = √100 = 10 m/s.
22.A ball falling from 10 m is halfway down (no air resistance). Compared with its starting energy:
Answer: D
It has lost half its height, so half its PE has become KE; the total is unchanged.
23.A ball dropped onto a hard floor bounces to a lower height each time because:
Answer: C
Each impact transfers some mechanical energy to heat and sound.
24.A 1000 kg car moving at 20 m/s has kinetic energy of:
Answer: C
KE = ½ × 1000 × 20² = 200 000 J.
25.A skier slides down a frictionless slope from rest, dropping 20 m. Her speed at the bottom is (g = 10 m/s²):
Answer: C
v = √(2 × 10 × 20) = √400 = 20 m/s.
26.Which example best shows an approximately isolated system?
Answer: B
A sealed vacuum flask exchanges very little energy or matter with its surroundings.
27.If a body's height above the ground is tripled, its gravitational PE becomes:
Answer: A
PE = mgh is proportional to h.
28.A spring gun uses 2 J of elastic energy to launch a 0.01 kg pellet straight up (no losses, g = 10 m/s²). How high does it rise?
Answer: C
mgh = 2 J, so h = 2 ÷ (0.01 × 10) = 20 m.
29.In a hydroelectric dam, the energy changes in order are:
Answer: D
Stored water has PE, which becomes KE as it falls, then electricity in the generator.
30.A closed system is one that:
Answer: B
A sealed pot of water on a stove is a closed system: heat enters but no steam escapes.
31.The total mechanical energy of a body in an isolated system with no friction remains constant.
Answer: True
This is the law of conservation of mechanical energy.
32.Kinetic energy depends on the square of the velocity.
Answer: True
KE = ½mv².
33.A heavy stone and a light stone dropped from the same height (no air resistance) reach the ground with the same speed.
Answer: True
v = √(2gh) does not depend on mass.
34.At the top of its swing, a pendulum bob has maximum kinetic energy.
Answer: False
At the top it is momentarily at rest, so its KE is zero and PE is maximum.
35.In a real system, some mechanical energy is usually converted to heat by friction.
Answer: True
That is why real pendulums and balls eventually stop.
36.The energy a body has due to its motion is called ______ energy.
Answer: kinetic
KE = ½mv².
37.The energy a body has due to its height is called gravitational ______ energy.
Answer: potential
PE = mgh.
38.The sum of kinetic and potential energy is called ______ energy.
Answer: mechanical
It is conserved when there is no friction.
39.A system that exchanges neither energy nor matter with its surroundings is called an ______ system.
Answer: isolated
Its total energy remains constant.
40.The speed of a body falling from rest through height h (no air resistance) is v = ______.
Answer: √(2gh)
From mgh = ½mv².
1.The three quantities that describe the state of a fixed mass of gas are:
Answer: C
The gas laws relate pressure, volume and temperature.
2.Boyle's law states that for a fixed mass of gas at constant temperature:
Answer: B
PV = constant at constant temperature.
3.The mathematical form of Boyle's law is:
Answer: D
P₁V₁ = P₂V₂ at constant temperature.
4.A gas occupies 6 m³ at 100 kPa. Its volume is reduced to 2 m³ at constant temperature. What is the new pressure?
Answer: A
P₂ = P₁V₁/V₂ = 100 × 6 ÷ 2 = 300 kPa.
5.A gas at 200 kPa occupies 30 cm³. At constant temperature, its pressure falls to 100 kPa. What is its new volume?
Answer: D
V₂ = P₁V₁/P₂ = 200 × 30 ÷ 100 = 60 cm³.
6.A graph of P against 1/V for a gas at constant temperature is:
Answer: A
P ∝ 1/V gives a straight line through the origin.
7.Charles's law states that for a fixed mass of gas at constant pressure:
Answer: C
V/T = constant when T is in kelvin.
8.To use the gas laws, temperature must be measured in:
Answer: A
The gas laws use absolute (kelvin) temperature.
9.Convert 27 °C to kelvin.
Answer: B
T(K) = θ(°C) + 273 = 27 + 273 = 300 K.
10.Convert 373 K to degrees Celsius.
Answer: C
θ = 373 − 273 = 100 °C.
11.A gas has volume 200 cm³ at 300 K. At constant pressure it is heated to 450 K. What is its new volume?
Answer: D
V₂ = V₁ × T₂/T₁ = 200 × 450 ÷ 300 = 300 cm³.
12.A sealed gas cylinder at 300 K has a pressure of 150 kPa. It is heated to 400 K. What is the new pressure?
Answer: B
P₂ = P₁ × T₂/T₁ = 150 × 400 ÷ 300 = 200 kPa.
13.Absolute zero is:
Answer: A
It is the lowest possible temperature, 0 K, about −273 °C.
14.At absolute zero, the particles of a substance would have:
Answer: D
Particle motion is at its minimum at absolute zero.
15.The general (combined) gas equation is:
Answer: C
It combines Boyle's, Charles's and the pressure laws.
16.A gas at 100 kPa, 2 m³ and 300 K is changed to 200 kPa and 600 K. What is its new volume?
Answer: A
V₂ = P₁V₁T₂/(T₁P₂) = 100 × 2 × 600 ÷ (300 × 200) = 2 m³.
17.Boyle's law can be explained by the kinetic theory: when the volume of a gas is halved at constant temperature,
Answer: B
Same speed, smaller space: more collisions per second per unit area.
18.When a gas is heated in a closed rigid container, its pressure rises because:
Answer: B
Higher temperature means greater particle speed.
19.An ideal gas is one that:
Answer: D
Real gases behave nearly ideally at low pressure and high temperature.
20.Why should the pressure be changed slowly in a Boyle's law experiment?
Answer: D
Rapid compression heats the gas, breaking the constant-temperature condition.
21.A bicycle tyre feels harder on a hot afternoon than in the cool morning because:
Answer: C
At nearly constant volume, pressure increases with temperature.
22.Aerosol cans carry a warning not to heat them because:
Answer: A
Heating a sealed can raises the internal gas pressure dangerously.
23.A bubble rises from the bottom of a lake to the surface. Its volume:
Answer: D
Pressure is lower near the surface, so by Boyle's law the bubble expands.
24.The volume–temperature graph of a gas at constant pressure, when extended backwards, meets the temperature axis at:
Answer: A
Extrapolating to zero volume gives absolute zero, about −273 °C.
25.A gas syringe contains 50 cm³ of air at 100 kPa. It is compressed to 25 cm³ at constant temperature. The new pressure is:
Answer: A
P₂ = 100 × 50 ÷ 25 = 200 kPa.
26.A gas at 0 °C is heated at constant pressure to 273 °C. Its volume:
Answer: C
273 K to 546 K doubles the absolute temperature, so volume doubles.
27.Gay-Lussac's law states that for a fixed mass of gas at constant volume:
Answer: C
P/T = constant at constant volume; it is also called the pressure law.
28.Dalton's law of partial pressures states that the total pressure of a mixture of gases is:
Answer: B
Each gas exerts its own pressure as if it were alone.
29.A container holds nitrogen at 60 kPa and oxygen at 40 kPa. What is the total pressure?
Answer: B
By Dalton's law, P_total = 60 + 40 = 100 kPa.
30.In the ideal gas equation PV = nRT, the symbol R stands for:
Answer: B
R ≈ 8.31 J/(mol K); n is the number of moles.
31.In Boyle's law, the temperature of the gas must be kept constant.
Answer: True
Boyle's law applies at constant temperature.
32.In gas law calculations, temperatures must be in degrees Celsius.
Answer: False
They must be in kelvin (absolute temperature).
33.If the pressure of a gas is doubled at constant temperature, its volume is halved.
Answer: True
PV = constant.
34.Absolute zero is equal to 0 °C.
Answer: False
Absolute zero is 0 K, about −273 °C.
35.Heating a gas at constant volume increases its pressure.
Answer: True
This is the pressure law: P ∝ T.
36.At constant temperature, PV = constant. This is ______'s law.
Answer: Boyle
Pressure is inversely proportional to volume.
37.At constant pressure, V/T = constant. This is ______'s law.
Answer: Charles
Volume is proportional to absolute temperature.
38.The lowest possible temperature, 0 K, is called absolute ______.
Answer: zero
It is about −273 °C.
39.To change a temperature from °C to kelvin, add ______.
Answer: 273
T(K) = θ(°C) + 273.
40.A gas that obeys the gas laws exactly is called an ______ gas.
Answer: ideal
Real gases approach ideal behaviour at low pressure.
1.Which of these materials is strongly attracted by a magnet?
Answer: C
Iron, nickel and cobalt are ferromagnetic.
2.Materials that are strongly attracted to magnets are called:
Answer: C
Ferromagnetic materials include iron, nickel, cobalt and steel.
3.According to the domain theory, a magnetic material is made of tiny regions called:
Answer: A
Each domain has its atomic magnets lined up in one direction.
4.In an unmagnetised piece of iron, the domains are:
Answer: B
Randomly arranged domains cancel each other out.
5.When a piece of iron is magnetised, its domains:
Answer: B
Aligned domains add together to give a strong magnet.
6.In atoms, magnetism comes mainly from the:
Answer: C
Moving and spinning electrons act like tiny current loops.
7.Which method can be used to magnetise a steel bar?
Answer: D
Single-touch or double-touch stroking aligns the domains.
8.The best way to make a strong magnet is the:
Answer: A
A strong direct current in a solenoid gives a powerful field to align the domains.
9.To magnetise a bar using a solenoid, the current must be:
Answer: D
Direct current gives a fixed field direction; alternating current demagnetises.
10.Which is a method of demagnetising a magnet?
Answer: A
Heat makes the domains vibrate and become random.
11.The best way to demagnetise a magnet is to:
Answer: B
The alternating field scrambles the domains as it weakens.
12.Hammering a magnet while it points east–west will:
Answer: A
The vibrations disturb the alignment of the domains.
13.Soft iron is used for the cores of electromagnets because it:
Answer: D
The electromagnet can then be switched on and off.
14.Steel is used to make permanent magnets because it:
Answer: D
Steel retains its magnetism well.
15.Magnetic keepers are used to:
Answer: B
Keepers form a closed loop so the domains stay aligned.
16.Bar magnets should be stored:
Answer: D
This closed arrangement prevents self-demagnetisation.
17.The law of magnetic poles states that:
Answer: B
N repels N, S repels S, and N attracts S.
18.The only sure test to find out whether a bar is a magnet is:
Answer: C
A magnet attracts unmagnetised iron too, so only repulsion proves it is a magnet.
19.Induced magnetism happens when:
Answer: A
The magnet's field aligns domains in the nearby material.
20.If a bar magnet is broken into two pieces, each piece:
Answer: B
Each piece still has aligned domains and two poles.
21.A freely suspended bar magnet comes to rest pointing:
Answer: B
It lines up with the Earth's magnetic field.
22.The temperature above which a ferromagnetic material loses its magnetism is called the:
Answer: C
Above the Curie temperature domains cannot stay aligned.
23.Magnetic field lines around a bar magnet go:
Answer: A
By convention, field lines leave the N pole and enter the S pole.
24.A magnet that keeps its magnetism for a long time is called a:
Answer: D
Permanent magnets are made of hard magnetic materials such as steel.
25.Which device uses a temporary (soft iron) electromagnet?
Answer: A
The bell's electromagnet switches on and off repeatedly.
26.Dropping a magnet repeatedly on a hard floor tends to:
Answer: B
Shocks disturb the aligned domains.
27.In the double-touch stroking method, the two stroking magnets:
Answer: A
Opposite poles start at the centre and stroke outwards to opposite ends.
28.A magnetic material that is magnetised by a magnet but loses its magnetism when the magnet is removed is called:
Answer: D
Soft magnetic materials such as soft iron form temporary magnets.
29.A magnetic compass is useful for navigation because its needle:
Answer: C
Travellers use it to find direction.
30.Which device uses a permanent magnet to change electrical signals into sound?
Answer: C
The magnet and a moving coil make the speaker cone vibrate.
31.In a magnetised bar, the domains point in random directions.
Answer: False
In a magnetised bar the domains are lined up.
32.Heating a magnet strongly can demagnetise it.
Answer: True
Heat randomises the domains.
33.Steel is better than soft iron for making permanent magnets.
Answer: True
Steel keeps its magnetism; soft iron loses it easily.
34.Copper is a ferromagnetic material.
Answer: False
Copper is non-magnetic.
35.Keepers help magnets keep their magnetism during storage.
Answer: True
They complete the magnetic circuit.
36.Small regions in a magnetic material in which atomic magnets are aligned are called ______.
Answer: domains
Aligned domains make the material a magnet.
37.Soft iron pieces placed across the ends of stored magnets are called magnetic ______.
Answer: keepers
They prevent loss of magnetism.
38.Iron, nickel and cobalt are called ______ materials.
Answer: ferromagnetic (magnetic)
They are strongly attracted to magnets.
39.To demagnetise a magnet electrically, it is placed in a solenoid carrying ______ current and slowly withdrawn.
Answer: alternating (AC)
The changing field scrambles the domains.
40.The region around a magnet where its magnetic force can be felt is called the magnetic ______.
Answer: field
It is shown by magnetic field lines.
1.An electric field is a region where:
Answer: B
Any charge placed in an electric field feels an electric force.
2.Electric field lines start on ______ charges and end on ______ charges.
Answer: D
By convention, field lines point away from positive and towards negative charges.
3.The direction of an electric field at a point is the direction of the force on:
Answer: D
Field direction is defined using a positive test charge.
4.Where electric field lines are close together, the field is:
Answer: B
Line density shows field strength.
5.Electric field lines never cross because:
Answer: B
Crossing would mean two directions of force at one point.
6.Electric field strength E is defined as:
Answer: A
E = F/q, measured in N/C (or V/m).
7.A charge of 2 × 10⁻⁶ C feels a force of 0.01 N in an electric field. What is the field strength?
Answer: A
E = F/q = 0.01 ÷ (2 × 10⁻⁶) = 5000 N/C.
8.The unit of electric field strength is:
Answer: D
Newtons per coulomb, equivalent to volts per metre.
9.The electric field between two parallel charged plates is:
Answer: C
Field lines between parallel plates are straight, parallel and evenly spaced.
10.Two parallel plates 0.02 m apart have a potential difference of 200 V. What is the field strength between them?
Answer: D
E = V/d = 200 ÷ 0.02 = 10 000 V/m.
11.The relationship between field strength E and potential difference V across a distance d in a uniform field is:
Answer: B
E = V/d for a uniform field.
12.The principle of superposition of electric fields means that the total field at a point is:
Answer: C
Fields from several charges add as vectors.
13.Midway between two equal positive charges, the electric field is:
Answer: D
The two fields are equal and opposite there, so they cancel.
14.Electric potential at a point is the:
Answer: A
Potential is measured in volts (joules per coulomb).
15.The unit of electric potential is the:
Answer: B
1 V = 1 J/C.
16.On a charged conductor, charge collects most densely at:
Answer: C
Charge concentrates at sharp points, giving strong fields there.
17.Charge on a hollow conductor resides:
Answer: D
Charges repel each other to the outer surface.
18.A lightning conductor works because:
Answer: A
Sharp points help charge leak away, and a thick copper strip carries any strike safely to earth.
19.A lightning conductor is usually made of:
Answer: A
Copper is a very good conductor.
20.A Van de Graaff generator is used to:
Answer: D
A moving belt carries charge to a dome, building up a very high voltage.
21.In a Van de Graaff generator, charge is carried to the dome by:
Answer: B
The belt picks up charge and carries it to the dome.
22.An electrostatic precipitator is used in factory chimneys to:
Answer: C
Charged particles are attracted to oppositely charged plates.
23.In an electrostatic precipitator, smoke particles are:
Answer: C
Collected particles are later shaken off and removed.
24.Electrostatic paint spraying is efficient because:
Answer: A
Less paint is wasted and hidden parts are also coated.
25.A danger of static electricity is:
Answer: A
That is why aircraft and fuel tankers are earthed while refuelling.
26.Fuel tankers are earthed while being emptied in order to:
Answer: A
Friction from flowing fuel can build up charge.
27.A positive point charge has electric field lines that:
Answer: C
Field lines leave a positive charge in all directions.
28.A charge of 3 μC is moved through a potential difference of 100 V. How much work is done?
Answer: C
W = qV = 3 × 10⁻⁶ × 100 = 3 × 10⁻⁴ J.
29.If the distance between two charged parallel plates is doubled at the same voltage, the field strength:
Answer: B
E = V/d, so doubling d halves E.
30.Two charges exert forces of 3 N and 5 N in the same direction on a third charge. What is the resultant force on it?
Answer: B
Parallel forces in the same direction add: 3 + 5 = 8 N.
31.Electric field lines can cross each other.
Answer: False
They never cross, as the field has only one direction at a point.
32.The electric field between two oppositely charged parallel plates is uniform.
Answer: True
Except near the edges, the lines are parallel and evenly spaced.
33.Charge on a conductor gathers most at sharp points.
Answer: True
This is why lightning conductors have pointed tips.
34.An electrostatic precipitator increases air pollution from chimneys.
Answer: False
It removes smoke and dust particles.
35.Electric potential is measured in volts.
Answer: True
1 V = 1 J/C.
36.Force per unit positive charge is called electric field ______.
Answer: strength (intensity)
E = F/q.
37.A machine with a moving belt that builds up high voltage on a metal dome is called a ______ generator.
Answer: Van de Graaff
It produces very high electrostatic voltages.
38.A pointed copper rod connected to earth to protect buildings is called a lightning ______.
Answer: conductor
It conducts charge safely to the ground.
39.For a uniform field, E = V ÷ ______.
Answer: d (distance between the plates)
Field strength = voltage per metre.
40.A device that removes dust from chimney gases using charged plates is an electrostatic ______.
Answer: precipitator
It attracts charged particles to collecting plates.
1.The first law of reflection states that the incident ray, reflected ray and normal:
Answer: B
All three lie in the same plane at the point of incidence.
2.The second law of reflection states that:
Answer: C
i = r, both measured from the normal.
3.The image in a plane mirror is:
Answer: D
Plane mirror images are virtual, upright, the same size and laterally inverted.
4.A concave mirror is a mirror whose reflecting surface:
Answer: C
Concave mirrors are also called converging mirrors.
5.A convex mirror is also called a:
Answer: A
It spreads reflected rays outwards.
6.The centre of the sphere of which a curved mirror is a part is called the:
Answer: B
It is marked C.
7.The relationship between the focal length f and the radius of curvature r is:
Answer: A
The principal focus lies halfway between the pole and the centre of curvature.
8.A concave mirror has a radius of curvature of 30 cm. Its focal length is:
Answer: D
f = r/2 = 30 ÷ 2 = 15 cm.
9.Rays parallel to the principal axis, after reflection from a concave mirror:
Answer: B
Concave mirrors converge parallel rays to the focus F.
10.A ray passing through the centre of curvature of a concave mirror is reflected:
Answer: B
It strikes the mirror along a normal, so it returns along itself.
11.An object placed beyond C in front of a concave mirror forms an image that is:
Answer: A
This arrangement is used in reflecting telescopes.
12.An object placed at C in front of a concave mirror forms an image that is:
Answer: A
Object and image are both at the centre of curvature.
13.An object placed between F and the pole of a concave mirror forms an image that is:
Answer: C
This is how shaving and make-up mirrors work.
14.When an object is placed exactly at F of a concave mirror, the image is formed:
Answer: D
The reflected rays are parallel and never meet.
15.The image formed by a convex mirror is always:
Answer: B
Convex mirrors always give small, upright, virtual images.
16.Convex mirrors are used as rear-view mirrors in cars because they:
Answer: A
Their diminished images let the driver see a large area behind.
17.Car headlamps and torches use concave mirrors with the bulb placed at the focus so that:
Answer: C
Light from F is reflected parallel to the axis.
18.Dentists use concave mirrors because, held close to a tooth, they give:
Answer: C
With the tooth inside F, the image is virtual and magnified.
19.The mirror formula (real-is-positive convention) is:
Answer: D
u is object distance, v image distance and f focal length.
20.An object is 30 cm from a concave mirror of focal length 10 cm. Where is the image?
Answer: C
1/v = 1/10 − 1/30 = 2/30, so v = 15 cm.
21.Magnification m of a mirror is given by:
Answer: D
m = v/u = image height ÷ object height.
22.For the object 30 cm from the mirror and image 15 cm from it, the magnification is:
Answer: C
m = v/u = 15 ÷ 30 = 0.5 (diminished).
23.An object is 20 cm from a concave mirror of focal length 15 cm. Where is the image?
Answer: B
1/v = 1/15 − 1/20 = 1/60, so v = 60 cm.
24.In the case above (u = 20 cm, v = 60 cm), the image is:
Answer: B
m = 60 ÷ 20 = 3, a real, inverted, magnified image.
25.A parabolic mirror is better than a spherical mirror for large apertures because it:
Answer: A
Wide spherical mirrors blur the focus (spherical aberration); parabolic ones do not.
26.Large concave mirrors used to cook food or heat water are called:
Answer: A
They focus sunlight onto a small area at F.
27.The point at the centre of a curved mirror's surface is called the:
Answer: D
It is marked P.
28.Mirrors placed at sharp road bends and in shops for security are:
Answer: D
Convex mirrors give a wide view.
29.A real image can be:
Answer: B
Real images are formed where rays actually meet.
30.A concave mirror has a focal length of 12 cm. Its radius of curvature is:
Answer: A
r = 2f = 24 cm.
31.The angle of incidence is equal to the angle of reflection.
Answer: True
This is the second law of reflection.
32.A convex mirror can form a real image on a screen.
Answer: False
A convex mirror always forms a virtual image.
33.The focal length of a curved mirror is half its radius of curvature.
Answer: True
f = r/2.
34.Shaving mirrors are convex mirrors.
Answer: False
They are concave, giving a magnified upright image when close.
35.A concave mirror can form both real and virtual images.
Answer: True
Real for objects beyond F, virtual for objects between F and P.
36.A curved mirror that bulges outwards is called a ______ mirror.
Answer: convex
It is a diverging mirror.
37.The point where rays parallel to the axis meet after reflection from a concave mirror is the principal ______.
Answer: focus
It is marked F.
38.Magnification = image distance ÷ ______ distance.
Answer: object
m = v/u.
39.Rear-view mirrors in vehicles are ______ mirrors.
Answer: convex
They give a wide field of view.
40.For a curved mirror, f = r ÷ ______.
Answer: 2
The focus is halfway between pole and centre of curvature.