Thermal Physics and HeatIB MYP Physics: Topic test

20 questions, 54 marks

IB MYP Physics

Thermal Physics and Heat topic test

Total 54 marks

Name

Class

Date

1
A metal lid is stuck tightly on a glass jar of pickles in a kitchen in Seoul. The cook runs hot water over the lid for a minute and the lid then turns easily.
(a)
Why does the lid come loose when it is heated?
[1 mark]
AThe metal lid expands more than the glass, so it fits more loosely
BThe particles in the metal become bigger and push the jar away
CThe glass contracts when it is touched by hot water
DThe lid loses mass when it is heated
(b)
Which statement about temperature is correct?
[1 mark]
ATemperature is the total thermal energy stored in an object
BTemperature is measured in joules
CTemperature is a measure of the average kinetic energy of the particles in an object
DTwo objects at the same temperature always store the same thermal energy
(c)
Explain, in terms of particles, why the metal lid expands when it is heated.
[2 marks]
Total for question 1: 4 marks
2
A hiker in Patagonia heats 0.50 kg of water from 10 °C to 60 °C on a small gas stove. The specific heat capacity of water is 4200 J/kg °C and that of olive oil is 2000 J/kg °C.
(a)
How much energy must be transferred to the water?
[1 mark]
A21 000 J
B126 000 J
C84 000 J
D105 000 J
(b)
The hiker transfers the same 105 000 J of energy to 0.50 kg of olive oil at 10 °C instead. Which statement about the temperature rise is correct?
[1 mark]
AIt is 50 °C, because the mass is the same
BIt is larger than 50 °C, because olive oil has a lower specific heat capacity
CIt is smaller than 50 °C, because olive oil has a lower specific heat capacity
DIt is zero, because oil cannot be heated on a gas stove
(c)
Give two reasons why the stove must supply more than 105 000 J of energy to heat the water.
[2 marks]
Total for question 2: 4 marks
3
A vacuum flask keeps coffee hot on a long coach journey in Kenya. The flask has a double-walled glass bottle with a vacuum between the walls. The surfaces facing the vacuum are silvered, and a plastic stopper closes the top.
(a)
Explain how the design of the flask reduces energy transfer by conduction, convection and radiation.
[3 marks]
(b)
A student wants to test the hypothesis that a vacuum flask keeps coffee hot for longer than a plain ceramic mug. Outline a method. Include the variable you will change, the variable you will measure and two variables you will control.
[4 marks]
Total for question 3: 7 marks
4
A student heats a test tube containing a pure solid in a beaker of water that is warmed by a Bunsen burner. She does not stir the water. She reads a thermometer in the solid to the nearest 1 °C every minute. The temperature rises steadily from 30 °C to 69 °C over 5 minutes. It then stays at 69 °C for 6 minutes while the solid melts. After that it rises steadily from 69 °C to 90 °C over 3 minutes. She does the experiment once.
(a)
Describe the pattern in the temperature readings and explain it in terms of particles and energy.
[6 marks]
(b)
Evaluate the student's method and suggest improvements.
[6 marks]
Total for question 4: 12 marks
5
In a bathroom in Berlin, a student takes a hot shower. Afterwards a cold mirror is covered in tiny droplets of water, but a heated mirror next to it stays clear. A puddle of water on the floor slowly disappears over the next hour.
(a)
Which statement explains the droplets on the cold mirror?
[1 mark]
AWater in the air boils when it touches the mirror
BWater vapour in the air loses energy to the cold mirror and condenses to liquid
CThe mirror gains energy and melts the water vapour
DWater evaporates from the mirror and leaves droplets behind
(b)
Which change would make the puddle evaporate faster?
[1 mark]
ACooling the room
BClosing the windows so the air stays still
CPouring the water into a narrow bucket
DOpening a window so that dry air moves over the puddle
(c)
State two differences between evaporation and boiling.
[2 marks]
Total for question 5: 4 marks
6
An electric iron in Warsaw contains a thermostat made from a bimetallic strip. The strip is a thin strip of brass joined to a thin strip of iron. When the iron becomes too hot, the strip bends and pulls apart a pair of contacts, which switches off the heating element. Brass expands more than iron for the same temperature rise.
(a)
What happens to the bimetallic strip when it is heated?
[1 mark]
AIt bends with the brass on the outside of the curve, because brass expands more
BIt bends with the brass on the inside of the curve, because brass expands more
CIt stays straight, because both metals expand
DIt bends with the iron on the outside of the curve, because iron expands more
(b)
What is the job of the bimetallic strip in the iron?
[1 mark]
AIt measures the thermal energy stored in the iron
BIt increases the current as the iron gets hotter
CIt switches off the heating element when the iron reaches a set temperature
DIt stops the iron from expanding
(c)
Describe one problem caused by thermal expansion in a large structure and one way in which engineers overcome it.
[2 marks]
Total for question 6: 4 marks
7
A student in Lisbon uses a 100 W electric heater to warm a 2.0 kg block of copper from 20 °C to 70 °C. The specific heat capacity of copper is 390 J/kg °C.
(a)
Calculate the energy needed to raise the temperature of the copper block.
[3 marks]
(b)
Calculate the time the heater would take if all of its energy went into the block. In the investigation the heating takes 450 s. Suggest why the real time is longer.
[4 marks]
Total for question 7: 7 marks
8
A housing council in Abu Dhabi is deciding whether all new apartment blocks must have flat roofs painted white and covered with a thick layer of insulation, instead of bare dark grey concrete. Summer temperatures reach 45 °C and the apartments rely on air conditioning. The insulation is a foam that traps tiny pockets of air.
(a)
Explain how the white paint and the insulation each help to keep the apartments cooler.
[6 marks]
(b)
Discuss whether the council should make white, insulated roofs compulsory for new apartment blocks.
[6 marks]
Total for question 8: 12 marks

End of questions

Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).