EnergyIB MYP Sciences: Topic test

20 questions, 54 marks

IB MYP Sciences

Energy topic test

Total 54 marks

Name

Class

Date

1
A girl in Buenos Aires stretches the rubber band of a toy catapult and releases it, launching a small paper ball across the room. The ball hits a wall and stops.
(a)
In which energy store is energy held while the band is stretched and held still?
[1 mark]
AKinetic
BElastic potential
CGravitational potential
DNuclear
(b)
What happens to the kinetic energy of the ball when it hits the wall and stops?
[1 mark]
AIt is destroyed
BIt is transferred to the chemical store of the wall
CIt is all stored as gravitational potential energy
DIt is transferred mainly to the thermal store of the surroundings
(c)
Describe the energy transfers from the moment the girl releases the band until the ball has stopped.
[2 marks]
Total for question 1: 4 marks
2
A hairdryer in a hair salon in Madrid is connected to the mains. Every second it transfers 2000 J of electrical energy. Of this, 1600 J each second is transferred usefully as thermal energy in the hot air and kinetic energy of the moving air. The rest is wasted.
(a)
What is the efficiency of the hairdryer?
[1 mark]
A80%
B20%
C125%
D40%
(b)
What is the power of the hairdryer?
[1 mark]
A2 W
B200 W
C2000 W
D20 000 W
(c)
Explain why the hairdryer cannot be 100% efficient.
[2 marks]
Total for question 2: 4 marks
3
A diver of mass 60 kg stands on a 10 m high platform at a swimming pool in Beijing and dives into the water. Use a gravitational field strength of 10 N/kg.
(a)
Calculate the diver's gravitational potential energy on the platform, and her speed just before she enters the water, assuming no energy is wasted.
[3 marks]
(b)
Describe the energy changes as the diver falls, and explain why her actual speed on entering the water is slightly lower than the value you calculated.
[4 marks]
Total for question 3: 7 marks
4
A new community centre in Reykjavik, Iceland, needs to heat its rooms and swimming pool. Students want to test which of three materials (foam, wool and aluminium foil) is best for insulating the hot-water pipes. The town can supply the heat from geothermal energy or from burning imported oil.
(a)
Plan an investigation to test a hypothesis about which of the three materials is the best insulator. In your answer, state a hypothesis with a scientific reason, identify the variables, and describe a safe method.
[6 marks]
(b)
Evaluate whether the community centre should use geothermal energy or burn imported oil to provide its heat. Give a justified conclusion.
[6 marks]
Total for question 4: 12 marks
5
On a sunny afternoon on a beach in Rio de Janeiro, the dark sand becomes much hotter than the sea. Later in the afternoon a cool breeze blows from the sea towards the land.
(a)
Which process mainly causes the cool breeze to blow from the sea to the land?
[1 mark]
AConduction
BRadiation
CConvection
DEvaporation
(b)
Which process transfers energy from the Sun to the sand?
[1 mark]
ARadiation
BConduction
CConvection
DInsulation
(c)
Explain how the sea breeze forms.
[2 marks]
Total for question 5: 4 marks
6
A sugar mill in Brazil burns the waste stalks left after sugar cane is crushed (bagasse) to make steam and produce electricity for the mill.
(a)
Why is the bagasse classed as a renewable energy resource?
[1 mark]
AIt releases no carbon dioxide when burned
BIt does not need to be burned to release energy
CIt is cheaper than every other fuel
DNew sugar cane can be grown quickly to replace it
(b)
Which of these energy resources used to generate electricity is non-renewable?
[1 mark]
ATidal
BNatural gas
CBiomass
DGeothermal
(c)
Outline how burning bagasse is used to generate electricity.
[2 marks]
Total for question 6: 4 marks
7
Students in Istanbul investigate how much energy it takes to heat a metal block. A 0.50 kg aluminium block, which has a specific heat capacity of 900 J/kg °C, is heated by a 60 W electric heater. The temperature of the block rises from 20 °C to 50 °C.
(a)
Calculate the energy transferred to the block and the minimum time the heater needs to supply this energy.
[3 marks]
(b)
In the experiment the heater actually took 300 s to produce this rise. Calculate the efficiency of the heating, and suggest one way to improve it.
[4 marks]
Total for question 7: 7 marks
8
In a village in Rajasthan, India, most households cook on gas stoves using bottled gas delivered by lorry. An aid group offers solar cookers, which are reflective dishes that focus sunlight on a pot. The village school tests one on a clear day by heating 1.0 kg of water by 40 °C three times with the solar cooker and three times with a gas stove.
(a)
The solar cooker took 46, 50 and 48 minutes. The gas stove took 8, 9 and 10 minutes. The specific heat capacity of water is 4200 J/kg °C. The students' hypothesis was that the gas stove transfers energy to the water faster than the solar cooker. Analyse the data to evaluate the hypothesis and the method.
[6 marks]
(b)
Evaluate whether the villagers should replace their gas stoves with solar cookers, using the results and your scientific knowledge. Give a justified conclusion.
[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).