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.

Questions courtesy of Eduqas.

Sample question 1 - Foundation

Question

A student carried out a practical to investigate the extension of a spring. Write a method the student could have used. [5 marks]

  1. set up a clamp stand with a clamp and hang a spring on it
  2. use another clamp and boss to fix a half metre rule alongside the spring
  3. record the metre rule reading that is level with the bottom of the spring
  4. hang a weight from the bottom of the spring
  5. record the new reading on the rule and the extension on the spring
  6. remove the weight and check the length of the spring
  7. repeat by adding more weights and record the readings on the rule

Steps should be logically ordered so that they could be followed by someone else to obtain valid results. [5]

Sample question 2 - Higher

Question

An experiment was carried out to investigate the elastic behaviour of a spring. The students added slotted masses to the spring and measured how much it stretched.

A clamp stand holds both a spring and a ruler. The spring has a weight hooked onto the bottom. The clamp is attached to a bench.
Mass applied to spring (g)Force (N)Loading: extension (cm)Unloading: extension (cm)Mean extension (cm)
10012.01.92.0
20024.04.04.0
30036.25.86.0
40048.27.88.0
50059.910.010.0

a) Suggest how the students could modify the apparatus to get more accurate results. [1 mark]

b) i) Use the data in the table and a recalled equation to calculate a value for the spring constant and give its unit. [3 marks]

ii) The elastic limit for this spring occurs for a load of 500 g. Describe what happens when loads bigger than this value are added to the spring. [1 mark]

c) Springs are used in chest expanders that are used as an exercise machine to strengthen the arms.

An expander consists of five springs in parallel held between two handles.

They each have a spring constant of 400 N/m.

i) Calculate the force that must be applied to the handles to stretch the expander by 50 cm. [4 marks]

ii) Give one change that could be made to the expander to decrease the force needed to stretch it by 50 cm. [1 mark]

iii) Choose an equation from the list to calculate the extra energy stored in the expander when it is stretched from 30 cm to 50 cm. [3 marks]

a) Use a pointer/place a ruler immediately behind the spring (to eliminate parallax errors). [1]

b) i) Substitution of an appropriate pair into k  =  \frac{F}{x} [1]

eg third reading k  =  3  \div  (6 \times 10^-2)  =  50 \ N/m [1]

Spring constant = 50 N/m [1]

ii) Any one of:

  • the spring becomes permanently stretched when the load is removed
  • extension is larger than 2 cm for every unit of load beyond 500 g

[1]

c) i) Conversion of 50 cm to 0.5 m [1]

For 1 spring F  =  kx  = 400 \times 0.5 = 200 \ N [2]

For 5 springs in parallel, F = 5 \times 200 = 1,000 \ N [1]

ii) Any one of:

  • remove a spring
  • use springs which have a smaller spring constant value

[1]

iii) Use of equation chosen from the list: E  =  0.5 \ k x^2 [1]

Energy stored at 30 cm = 5 × (0.5 × 400 × 0.32) = 90 J

Energy stored at 50 cm = 5 × (0.5 × 400 × 0.52) = 250 J [1]

Increase in energy = 250 - 90 = 160 J [1]