# Energy - Practical questions

You will complete twelve Specified Practical Activities if you are studying GCSE Physics. You could be asked questions about the apparatus, methods, safety precautions, results, analysis and evaluation of these experiments.

These questions have been written by Bitesize consultants as suggestions to the types of questions that may appear in an exam paper.

## Sample question 1 - Foundation

Question

A teacher gives a pupil a spring and gives a challenge to find how much energy the particular spring stores when extended by 2.5 cm. The pupil then performs an experiment by hanging the spring on a stand and adding 1 N weights to it and measuring the extension each time. Here are the results:

Force1 N2 N3 N4 N5 N6 N7 N
Extension0.5 cm1 cm1.5 cm2 cm2.5 cm3 cm3.5 cm

a) Plot a graph of the results. [3 marks]

b) Use the graph to find a value for the spring constant of the spring. [2 marks]

c) Use a formula you have used before to find the energy stored in the spring when extended by 2.5 cm. [2 marks]

a)

• choice of correct scales 
• all points plotted 
• straight line with ruler 

b) Gradient = k = 7 ÷ 3.5 

= 2 N/cm 

c) Energy in a stretched spring = ## Sample question 2 - Higher

Question

A pupil used the following apparatus to find the specific heat capacity of aluminium:

The pupil then performed the experiment using the instructions below:

• ensure the power supply is switched off
• place the immersion heater and thermometer in the holes provided in the 1 kg aluminium block
• record the initial temperature of the aluminium block
• switch on the 12 V power supply
• record the temperature of the 1 kg aluminium block after 10 minutes

a) Which one essential piece of apparatus is missing from the diagram? [1 mark]

b) Outline one hazard when performing this experiment. [1 mark]

c) Calculate the energy supplied from a 10 W heater in the 10 minutes by using an equation you remember. [2 marks]

d) The initial temperature was 15°C and the final temperature was 20.5°C. What is the temperature rise? [1 mark]

e) Choose an equation from the list to find the specific heat capacity of aluminium. [3 marks]

f) If your answer is different to the accepted value of 920 J/kg°C try to give an explanation of why it is so. [1 mark]

g) Another pupil performed the same experiment with the same heater for the same time on a 1kg block of Iron. If iron has a specific heat capacity of 460 J/kg°C, what main difference would you see in the results of the experiment? [2 marks]

a) Lagging/insulation/stop clock 

b) The hot immersion heater can burn 

c) Power = energy ÷ time in seconds

Energy = power × time in seconds = 10 × (10 × 60) 

Energy = 6,000 J 

d) 20.5°C - 15°C = 5.5°C 

e)   = 6,000 ÷ (1 x 5.5) 

= 1,091 J/kg°C 

f) It is a bigger value because some of the heat energy from the heater is lost to the surroundings. 

g) The temperature rise would be greater ; in fact double/twice as much .