Thermal Properties and Temperature

Chapter 12 MCQs

For Full Scale Course: Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total Personal A Grades, 11 World Records and 7 Distinctions, Educate A Change.

1

A metal rod is heated from 20°C to 120°C. Its length increases from 1.000 m to 1.0012 m.

What is the increase in length per metre per °C?

A 1.2 × 10⁻⁶ /°C
B 1.2 × 10⁻⁵ /°C
C 1.2 × 10⁻⁴ /°C
D 1.2 × 10⁻³ /°C

2

A metal wire has length 2.0 m at 20°C. It expands by 0.96 mm when heated to 100°C.

What is the expansion per metre per °C?

A 6.0 × 10⁻⁶ /°C
B 1.2 × 10⁻⁵ /°C
C 2.4 × 10⁻⁵ /°C
D 4.8 × 10⁻⁴ /°C

3

A brass strip and an iron strip are riveted together to form a bimetallic strip. Brass expands more than iron.

The strip is heated.

Which statement is correct?

A It bends with brass on the inside of the curve.
B It bends with iron on the inside of the curve.
C It remains straight because both metals are heated equally.
D It contracts because metals always contract when heated.

4

A bimetallic strip is used in a fire alarm. When heated, it bends and completes an electrical circuit.

Which property makes this possible?

A metals conduct electricity equally well
B different metals expand by different amounts
C metals have zero resistance when hot
D metals lose mass when heated

5

A railway track has small gaps between sections.

Why are these gaps needed?

A to allow expansion in hot weather
B to allow contraction in hot weather
C to increase the density of the rails
D to stop sound travelling through the rails

6

A metal ring is heated uniformly.

What happens to the diameter of the hole in the ring?

A decreases because metal expands inwards
B stays the same because there is no metal in the hole
C increases because all dimensions expand
D becomes zero because the metal closes the hole

7

A tight metal lid on a glass jar is placed under hot water.

Why can this help remove the lid?

A the glass expands much more than the metal
B the metal lid expands and becomes slightly larger
C the pressure inside the jar becomes zero
D the metal lid contracts because it is heated

8

A liquid-in-glass thermometer works mainly because:

A glass expands but the liquid does not
B the liquid expands more than the glass
C the liquid contracts when heated
D the glass melts slightly when heated

9

A thermometer bulb contains mercury. The mercury expands when temperature increases.

Which change makes the thermometer more sensitive?

A use a wider capillary tube
B use a narrower capillary tube
C use a thicker glass bulb
D use a smaller bulb with less mercury

10

A liquid thermometer has a large bulb and a narrow capillary.

What is the main reason for this design?

A to increase the mass of glass
B to produce a larger movement of liquid for a small temperature change
C to make the liquid boil at room temperature
D to make the thermometer insensitive to temperature changes

For Full Scale Course: Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total Personal A Grades, 11 World Records and 7 Distinctions, Educate A Change.

11

A student heats air in a balloon. The balloon expands.

Which statement best explains the expansion?

A air particles become larger
B air particles move faster and take up more space on average
C air particles become heavier
D air particles attract each other more strongly

12

A sealed rigid metal can contains gas. The gas is heated but the can does not expand.

What increases?

A volume of gas only
B pressure of gas only
C mass of gas only
D number of gas particles only

13

Which state of matter usually expands the most for the same temperature rise?

A solid
B liquid
C gas
D all expand equally

14

A solid, a liquid and a gas are heated by the same temperature rise.

Which row shows the usual order of expansion, from least to greatest?

A gas, liquid, solid
B liquid, gas, solid
C solid, liquid, gas
D solid, gas, liquid

15

A metal bridge is built with expansion joints.

Which change would make the joints need to allow for a greater expansion?

A shorter bridge and smaller temperature range
B longer bridge and larger temperature range
C shorter bridge and larger temperature range
D longer bridge and smaller temperature range only

16

A steel rod expands by 0.30 mm when heated by 50°C.

Assuming proportionality, what expansion occurs when the same rod is heated by 80°C?

A 0.19 mm
B 0.30 mm
C 0.48 mm
D 0.80 mm

17

A wire expands by 1.2 mm when heated from 20°C to 80°C.

Assuming expansion is proportional to temperature change, what is the expansion when heated from 20°C to 50°C?

A 0.30 mm
B 0.60 mm
C 0.90 mm
D 2.4 mm

18

A steel ruler is calibrated at 20°C. It is used at 80°C to measure the length of a metal object whose temperature remains 20°C.

The steel ruler has expanded.

What happens to the measured length shown by the ruler?

A it is too small
B it is too large
C it is unchanged
D it becomes zero

19

A metal ball just fits through a metal ring at room temperature. The ball alone is heated.

What happens?

A the ball passes through more easily
B the ball no longer passes through
C the ring expands too
D the ball loses weight and falls through

20

A metal ball and metal ring are both heated by the same temperature rise. They are made of the same metal.

If the ball just fitted through the ring before heating, what happens after heating?

A the ball still just fits through
B the ball definitely cannot pass through
C the ball passes through more easily
D the ring hole contracts

21

Which statement about absolute zero is correct?

A it is 0°C
B it is approximately −273°C
C it is the boiling point of nitrogen
D it is the temperature where water freezes

22

What is 27°C in kelvin?

A 246 K
B 273 K
C 300 K
D 327 K

23

A temperature is 450 K.

What is this temperature in °C?

A 177°C
B 273°C
C 450°C
D 723°C

24

A gas is heated from 20°C to 80°C.

What is the temperature rise in kelvin?

A 60 K
B 80 K
C 293 K
D 353 K

25

Two thermometers measure the same temperature change.

Thermometer X shows a change from 10°C to 40°C. Thermometer Y uses kelvin.

What temperature change does Y show?

A 30 K
B 40 K
C 283 K
D 313 K

For Full Scale Course: Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total Personal A Grades, 11 World Records and 7 Distinctions, Educate A Change.

26

Which statement best describes internal energy?

A the total kinetic energy of the object only
B the total potential energy of the object only
C the total kinetic and potential energy of the particles in the object
D the energy stored only because the object is moving as a whole

27

A metal block is heated but does not melt.

Which statement is correct?

A internal energy increases because particle kinetic energy increases
B internal energy decreases because particles lose potential energy
C internal energy is unchanged because the block remains solid
D internal energy becomes zero because particles stay in fixed positions

28

During melting at constant temperature, energy is supplied to a solid.

What mainly happens to the internal energy?

A it decreases because temperature is constant
B it increases because particle potential energy increases
C it remains constant because kinetic energy is constant
D it becomes zero because bonds vanish completely

29

During a temperature rise with no change of state, what happens to the average kinetic energy of particles?

A decreases
B stays constant
C increases
D becomes independent of temperature

30

During a change of state at constant temperature, what happens to the average kinetic energy of particles?

A it stays constant
B it increases continuously
C it decreases continuously
D it becomes zero

31

A 0.50 kg block is heated. Its temperature rises by 40°C. The specific heat capacity of the block is 900 J/(kg°C).

How much energy is supplied?

A 11 J
B 18 000 J
C 45 000 J
D 72 000 J

32

A 2.0 kg liquid is heated by 25°C. Its specific heat capacity is 4200 J/(kg°C).

How much energy is needed?

A 84 J
B 52 500 J
C 105 000 J
D 210 000 J

33

A metal block of mass 0.80 kg receives 12 000 J of energy. Its temperature rises by 30°C.

What is its specific heat capacity?

A 320 J/(kg°C)
B 500 J/(kg°C)
C 288 000 J/(kg°C)
D 450 000 J/(kg°C)

34

A substance has mass 250 g and specific heat capacity 800 J/(kg°C). It receives 6000 J of energy.

What is its temperature rise?

A 0.030°C
B 7.5°C
C 30°C
D 120°C

35

A heater of power 60 W heats 0.20 kg of water for 5.0 minutes. Assume no energy is lost.

Specific heat capacity of water = 4200 J/(kg°C).

What is the temperature rise?

A 4.3°C
B 21°C
C 43°C
D 1500°C

36

A 12 V heater takes a current of 3.0 A and heats a 0.50 kg block for 4.0 minutes. The temperature of the block rises by 24°C.

Assuming no energy loss, what is the specific heat capacity of the block?

A 30 J/(kg°C)
B 720 J/(kg°C)
C 1440 J/(kg°C)
D 17 280 J/(kg°C)

37

A 24 W heater is used to heat 0.30 kg of oil. The oil’s temperature rises from 20°C to 60°C in 7.0 minutes.

Assuming no energy loss, what is the specific heat capacity of the oil?

A 840 J/(kg°C)
B 1200 J/(kg°C)
C 2100 J/(kg°C)
D 28 000 J/(kg°C)

38

A student heats a 0.10 kg metal block using a 40 W heater. The temperature rises by 50°C in 2.0 minutes.

What value of specific heat capacity is calculated if all heater energy is assumed to heat the block?

A 9.6 J/(kg°C)
B 96 J/(kg°C)
C 960 J/(kg°C)
D 9600 J/(kg°C)

39

In an experiment to find specific heat capacity, the electrical heater transfers 5000 J, but 800 J is lost to the surroundings. The mass is 0.20 kg and temperature rise is 25°C.

What is the actual specific heat capacity of the material?

A 840 J/(kg°C)
B 1000 J/(kg°C)
C 1160 J/(kg°C)
D 25 000 J/(kg°C)

40

A student ignores heat loss to the surroundings when finding the specific heat capacity of a metal block using an electric heater.

What is the likely effect on the calculated specific heat capacity?

A it is too small
B it is too large
C it is exactly correct
D it becomes zero

For Full Scale Course: Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total Personal A Grades, 11 World Records and 7 Distinctions, Educate A Change.

41

A metal block is heated electrically. The heater power is known.

Which measurements are needed to determine the specific heat capacity of the block?

A mass, temperature rise and time
B mass, volume and time only
C weight, pressure and temperature rise
D current only

42

A student uses an electric heater to find the specific heat capacity of a metal block.

Which change improves accuracy?

A leave the block uninsulated
B use a dull black block to increase radiation loss
C insulate the block and use oil in the thermometer hole
D use a smaller temperature rise to increase percentage uncertainty

43

Why is oil placed in the thermometer hole in a metal block during a specific heat capacity experiment?

A to reduce the mass of the block
B to improve thermal contact between thermometer and block
C to stop electricity flowing through the heater
D to make the thermometer read room temperature only

44

A student heats a block with a 50 W heater for 100 s. The block has mass 0.50 kg and specific heat capacity 400 J/(kg°C).

If no energy is lost, what is the temperature rise?

A 10°C
B 25°C
C 40°C
D 250°C

45

A temperature–time graph is plotted while a liquid is heated by a constant-power heater.

If there are no energy losses and no change of state, what does the gradient represent?

A mass × specific heat capacity
B power / thermal capacity
C specific heat capacity / power
D temperature × time

46

Two equal-power heaters separately heat equal masses of two liquids for the same time. Liquid X has a smaller temperature rise than liquid Y.

Assuming no energy loss, which statement is correct?

A X has a smaller specific heat capacity
B X has a larger specific heat capacity
C X has the same specific heat capacity as Y
D X has no internal energy

47

Equal masses of copper and water receive the same energy. The temperature rise of copper is greater than that of water.

Which statement is correct?

A copper has a larger specific heat capacity
B copper has a smaller specific heat capacity
C both have equal specific heat capacity
D water receives less energy

48

A hot metal block is placed into cold water in an insulated container. Assume no energy is lost to the surroundings.

Which statement is correct?

A energy lost by metal = energy gained by water
B temperature fall of metal = temperature rise of water
C specific heat capacity of metal = specific heat capacity of water
D final temperature must be halfway between the initial temperatures

49

A 0.20 kg hot metal block at 100°C is placed in 0.50 kg of water at 20°C. Final temperature is 24°C. Specific heat capacity of water = 4200 J/(kg°C). No energy is lost.

What is the specific heat capacity of the metal?

A 110 J/(kg°C)
B 210 J/(kg°C)
C 550 J/(kg°C)
D 4200 J/(kg°C)

50

A student uses a heater to find the specific heat capacity of water. The heater warms both the water and the container, but the student calculates using only the mass of water.

What is the likely effect on the calculated value for water?

A too small because extra energy heats the container
B too large because extra energy heats the container
C unchanged because container temperature does not change
D zero because water cannot store internal energy

For Full Scale Course: Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total Personal A Grades, 11 World Records and 7 Distinctions, Educate A Change.

Chapter 12 Answer Key

Q	Ans	Q	Ans	Q	Ans	Q	Ans	Q	Ans
1	B	11	B	21	B	31	B	41	A
2	A	12	B	22	C	32	D	42	C
3	B	13	C	23	A	33	B	43	B
4	B	14	C	24	A	34	C	44	B
5	A	15	B	25	A	35	B	45	B
6	C	16	C	26	C	36	B	46	B
7	B	17	B	27	A	37	A	47	B
8	B	18	A	28	B	38	C	48	A
9	B	19	B	29	C	39	A	49	C
10	B	20	A	30	A	40	B	50	B

For Full Scale Course: Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total Personal A Grades, 11 World Records and 7 Distinctions, Educate A Change.

Detailed Explanations

1. B

Increase in length = 1.0012 − 1.000 = 0.0012 m
Temperature rise = 120 − 20 = 100°C
Expansion per metre per °C = 0.0012 / (1.000 × 100)
= 1.2 × 10⁻⁵ /°C

2. A

Expansion = 0.96 mm = 0.00096 m
Original length = 2.0 m
Temperature rise = 100 − 20 = 80°C
Expansion per metre per °C = 0.00096 / (2.0 × 80)
= 0.00096 / 160
= 6.0 × 10⁻⁶ /°C

3. B

Brass expands more than iron.
The metal that expands more forms the outside of the curve.
Iron expands less, so it is on the inside of the curve.
Answer = iron on the inside

4. B

A bimetallic strip bends because two metals expand by different amounts.
This bending can close a circuit in a fire alarm.
The key idea is different thermal expansion, not electrical conductivity.

5. A

Railway tracks expand in hot weather.
Gaps allow room for expansion.
Without gaps, rails may bend or buckle.

6. C

When a metal ring is heated, all dimensions expand.
The hole behaves as if it also expands.
The diameter of the hole increases.
Trap: metal does not only expand inwards.

7. B

Hot water heats the metal lid.
The metal lid expands slightly.
Its diameter becomes larger, making it easier to remove.

8. B

A liquid-in-glass thermometer works because the liquid expands more than the glass.
The expanding liquid rises in the narrow tube.
If glass expanded more, the thermometer would be useless behaviour-wise.

9. B

Sensitivity means a small temperature change gives a large movement of liquid.
A narrower capillary means the same volume expansion rises further.
So a narrower capillary increases sensitivity.

10. B

Large bulb = more liquid expands.
Narrow capillary = small volume expansion causes large height rise.
This gives a larger movement for a small temperature change.

11. B

Heating air increases the average kinetic energy of its particles.
The particles move faster.
In a flexible balloon, the gas expands and occupies a larger volume.
Particles do not become larger; their spacing increases.

12. B

The container is sealed and rigid.
Mass and volume remain constant.
Heating makes gas particles move faster.
Collisions with the walls become more forceful/frequent.
Pressure increases.

13. C

Gases usually expand the most for the same temperature rise.
Liquids expand less than gases.
Solids usually expand the least.

14. C

Usual expansion order from least to greatest:
- solid
- liquid
- gas
Answer = solid, liquid, gas

15. B

Expansion increases when:
- original length is greater
- temperature change is greater
A longer bridge with a larger temperature range needs larger expansion joints.

16. C

Expansion is proportional to temperature rise.
50°C gives 0.30 mm.
80°C gives:
- 0.30 × 80 / 50
- = 0.48 mm

17. B

From 20°C to 80°C:
- temperature rise = 60°C
- expansion = 1.2 mm
From 20°C to 50°C:
- temperature rise = 30°C
Expansion = 1.2 × 30 / 60
= 0.60 mm

18. A

The steel ruler expands, so each division becomes slightly longer.
The same object covers fewer ruler divisions.
Therefore the measured length shown is too small.
Sneaky but very exam-style.

19. B

The ball alone is heated.
The ball expands.
The ring stays the same size.
So the ball no longer passes through.

20. A

Ball and ring are made of the same metal and heated by the same temperature rise.
Both expand by the same proportion.
The ball still just fits through the ring.

For Full Scale Course: Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total Personal A Grades, 11 World Records and 7 Distinctions, Educate A Change.

21. B

Absolute zero is approximately −273°C.
On the Kelvin scale, absolute zero is 0 K.

22. C

Kelvin = °C + 273
27°C = 27 + 273
= 300 K

23. A

°C = K − 273
450 K = 450 − 273
= 177°C

24. A

Temperature rise in °C is equal in size to temperature rise in K.
80°C − 20°C = 60°C
Temperature rise = 60 K

25. A

Temperature changes have the same numerical size in °C and K.
40°C − 10°C = 30°C
Kelvin change = 30 K

26. C

Internal energy is the total kinetic and potential energy of the particles in a substance.
Kinetic part relates to particle motion.
Potential part relates to forces/separation between particles.

27. A

The block is heated but does not melt.
Temperature rises.
Average kinetic energy of particles increases.
Therefore internal energy increases.

28. B

During melting, temperature stays constant.
Average kinetic energy stays constant.
Energy supplied increases the potential energy of particles as bonds/forces are overcome.
Internal energy still increases.

29. C

During a temperature rise with no change of state, particles move faster on average.
Average kinetic energy increases.

30. A

During change of state, temperature remains constant.
Average kinetic energy depends on temperature.
Therefore average kinetic energy stays constant.
Energy supplied changes potential energy instead.

31. B

Energy = mcΔθ
E = 0.50 × 900 × 40
E = 18 000 J

32. D

Energy = mcΔθ
E = 2.0 × 4200 × 25
E = 210 000 J

33. B

E = mcΔθ
c = E / mΔθ
c = 12 000 / (0.80 × 30)
c = 12 000 / 24
c = 500 J/(kg°C)

34. C

Mass = 250 g = 0.250 kg
E = mcΔθ
Δθ = E / mc
Δθ = 6000 / (0.250 × 800)
Δθ = 6000 / 200
Δθ = 30°C

35. B

Energy supplied = power × time
Time = 5.0 minutes = 300 s
E = 60 × 300 = 18 000 J
Δθ = E / mc
Δθ = 18 000 / (0.20 × 4200)
Δθ = 18 000 / 840
Δθ = 21°C

For Full Scale Course: Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total Personal A Grades, 11 World Records and 7 Distinctions, Educate A Change.

36. B

Electrical energy = VIt
Time = 4.0 minutes = 240 s
E = 12 × 3.0 × 240
E = 8640 J
c = E / mΔθ
c = 8640 / (0.50 × 24)
c = 8640 / 12
c = 720 J/(kg°C)

37. A

Time = 7.0 minutes = 420 s
Energy = Pt = 24 × 420 = 10 080 J
Temperature rise = 60 − 20 = 40°C
c = E / mΔθ
c = 10 080 / (0.30 × 40)
c = 10 080 / 12
c = 840 J/(kg°C)

38. C

Time = 2.0 minutes = 120 s
Energy = Pt = 40 × 120 = 4800 J
c = E / mΔθ
c = 4800 / (0.10 × 50)
c = 4800 / 5
c = 960 J/(kg°C)

39. A

Energy transferred to material = 5000 − 800
Energy = 4200 J
c = E / mΔθ
c = 4200 / (0.20 × 25)
c = 4200 / 5
c = 840 J/(kg°C)

40. B

If heat loss is ignored, the student assumes all electrical energy heats the block.
But some energy is lost to surroundings.
The energy used in the calculation is too large.
c = E / mΔθ becomes too large.
Calculated specific heat capacity is too large.

41. A

To find specific heat capacity:
- E = Pt
- E = mcΔθ
Needed measurements:
- mass
- temperature rise
- time
If heater power is known, current and voltage are not both needed.

42. C

Insulation reduces heat loss.
Oil in the thermometer hole improves thermal contact.
This makes the thermometer reading closer to the actual block temperature.

43. B

Oil fills air gaps around the thermometer.
It improves thermal contact between thermometer and metal block.
Better contact gives a more accurate temperature reading.

44. B

Energy supplied = Pt
E = 50 × 100 = 5000 J
Δθ = E / mc
Δθ = 5000 / (0.50 × 400)
Δθ = 5000 / 200
Δθ = 25°C

45. B

For constant power:
- P = mc × Δθ / t
So gradient of temperature–time graph:
- Δθ / t = P / mc
mc is thermal capacity.
Gradient = power / thermal capacity

46. B

Equal power for equal time means equal energy supplied.
Equal masses are heated.
E = mcΔθ
If X has smaller temperature rise, c must be larger.
Liquid X has a larger specific heat capacity.

47. B

Equal masses receive equal energy.
Copper has greater temperature rise.
E = mcΔθ
For same E and m, larger Δθ means smaller c.
Copper has smaller specific heat capacity.

48. A

In an insulated container with no energy loss:
- energy lost by hot metal = energy gained by cold water
Temperature changes do not need to be equal.
Specific heat capacities do not need to be equal.
Final temperature is not necessarily halfway.

49. C

Water gains energy:
- E = mcΔθ
- E = 0.50 × 4200 × (24 − 20)
- E = 0.50 × 4200 × 4
- E = 8400 J
Metal loses same energy = 8400 J
Metal temperature fall:
- 100 − 24 = 76°C
cmetal = E / mΔθ
c = 8400 / (0.20 × 76)
c = 8400 / 15.2
c ≈ 550 J/(kg°C)

50. B

The heater warms both the water and the container.
The student uses total heater energy but only mass of water.
This makes the energy value too large for the water alone.
c = E / mΔθ becomes too large.
Calculated value is too large.

For Full Scale Course: Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total Personal A Grades, 11 World Records and 7 Distinctions, Educate A Change.

Common Traps From This Chapter

Trap	Correct Rule
Expansion of metal ring	hole expands too
Bimetallic strip	more expanding metal goes outside curve
Railway gaps	allow expansion in hot weather
Thermometer sensitivity	large bulb + narrow capillary
Gas expands most	gases usually expand more than liquids and solids
Expanded ruler	measured length becomes too small
Absolute zero	about −273°C
Celsius to kelvin	K = °C + 273
Temperature change	1°C change = 1 K change
Internal energy	total kinetic + potential energy of particles
Temperature rise	average kinetic energy increases
Change of state	average kinetic energy constant, potential energy changes
Specific heat capacity	E = mcΔθ
Electrical heating energy	E = VIt or Pt
Minutes to seconds	multiply by 60
Grams to kg	divide by 1000
Ignoring heat loss	calculated c usually too large
Oil in thermometer hole	improves thermal contact
Insulation	reduces heat loss
Mixing hot metal and cold water	energy lost = energy gained
Container also heated	calculated c for water becomes too large

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