Three and four mark questions
These are similar to one- and two-mark questions but you will be expected to write in more depth for three- and four-mark questions.
The answers here give lists of valid points that could be included in your answer.
Sample question 1 - Foundation
Question
A car driver sees a fallen tree lying across the road ahead and makes an emergency stop.
The braking distance of the car depends on the speed of the car. For the same braking force, explain what happens to the braking distance if the speed doubles.
You should refer to kinetic energy in your answer. [4 marks]
This question has been written by a Bitesize consultant as a suggestion to the type of question that may appear in an exam paper.
Intentionally mention key points such as:
- doubling speed increases the kinetic energy
- kinetic energy increases by a factor of four
- work done (by brakes) to stop the car increases
- work done increases by a factor of four
- work done is force × distance and braking force is constant
- so if work done increases by 4 then the braking distance must increase by four
[4]
With a question like this it's often sensible to plan a loose outline of your answer beforehand. Using bullet points in your answer can help you structure your answer to include enough relevant points.
Sample question 2 - Foundation
Question
A car has a mass of 1,650 kg. This table shows the kinetic energy of the car moving at 11 m/s.
| Mass of car (kg) | Speed (m/s) | Kinetic energy (J) |
| 1,650 | 11 | 99,825 |
| 1,650 | 30 | ______ |
| Mass of car (kg) | 1,650 |
|---|---|
| Speed (m/s) | 11 |
| Kinetic energy (J) | 99,825 |
| Mass of car (kg) | 1,650 |
|---|---|
| Speed (m/s) | 30 |
| Kinetic energy (J) | ______ |
Calculate the missing value in the table.
Give your answer in kilojoules (kJ). [3 marks]
This question is AQA material which is reproduced by permission of AQA.
kinetic energy = 0.5 × mass × (speed)2 [1]
0.5 × 1,650 × 302 [1]
= 742.5 (kJ) [1]
Be sure to show all stages of calculations. Write out the equation in full, and the full calculations to be performed. Also, write out the final answer with the right units.
Sample question 3 - Higher
Question
The UK produces most of its electricity from fossil fuels.
Many people in the UK leave their televisions in 'stand by' mode when not in use, instead of switching them off.
It is better for the environment if people switch off their televisions, instead of leaving them in 'stand by' mode.
Explain why. [3 marks]
This question is AQA material which is reproduced by permission of AQA.
TVs in stand by use electricity [1]. Generating electricity (from fossil fuels) produces CO2 [1]. CO2 contributes to global warming [1].
Breaking the answer down into stages can help make sure that enough scientific points have been included.
Sample question 4 - Higher
Question
A driver wishes to buy a new car.
This table gives some data about an electric car and one with a petrol engine.
| Electric car | Petrol engine car | |
| Cost (£) | 27,000 | 15,000 |
| Running cost per year (£) | 250 | 2,000 |
| Average lifetime (years) | 12 | 12 |
| Cost (£) | |
|---|---|
| Electric car | 27,000 |
| Petrol engine car | 15,000 |
| Running cost per year (£) | |
|---|---|
| Electric car | 250 |
| Petrol engine car | 2,000 |
| Average lifetime (years) | |
|---|---|
| Electric car | 12 |
| Petrol engine car | 12 |
Which car would be the most economical over its 12-year lifetime?
Use data from the table to support your answer.
You should include the difference in cost in your answer. [4 marks]
This question is AQA material which is reproduced by permission of AQA.
Use the figures to compare the two vehicles and form a conclusion of which is most economical. The answer should include a range of the following points:
- the electric car costs £12,000 more to buy
- running cost of electric car = £3,000
- running cost of petrol engine car = £24,000
- total cost of electric car = £30,000
- total cost of petrol engine car = £39,000
- the electric car cost £1,750 less to run each year
- the electric car will save £9,000
- so the electric car will be cheaper over the 12-year lifetime
[4]
Not all of these statements are needed but at least four should be included to have the best chance of accessing all the available marks.
