One to two mark questions will start with command words such as 'describe' or 'explain'. Some command words are easy to understand such as:
The command words 'describe' and 'explain' can be confusing. If you are asked to describe a graph, you will be expected to write about its overall shape, whether it is linear or curved, the slope of gradients etc. If you are asked to explain why a pattern or trend is seen in a graph, you will be expected to use your science knowledge, not just say what you see (which is a description), eg 'The graph shows a steep linear increase for the first three hours because…'.
'Explain how' and 'why' questions often have the word 'because' in their answer. 'Describe' questions don't.
The number of marks per question part is given in this form '[2 marks]'. It is essential that you give two different answers if a question is worth two marks. Sometimes you can gain a second mark by giving the units in a calculation or stating specific data points, eg 'the speed of the object decreased by 8 m/s'.
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Coal is a non-renewable energy resource.
Name two other non-renewable energy resources. [2 marks]
Any two from:
There are two marks for this question so you must be prepared to write at least two points for the best chance of getting all available marks.
A wind turbine has an average power output of 0.60 MW.
A coal-fired power station has a continuous power output of 1,500 MW.
Calculate how many wind turbines would be needed to generate the same power output as one coal-fired power station. [2 marks]
If one turbine provides 0.6 MW, then to find out how many are required to generate 1,500 MW you need to divide 1,500 by 0.6.
1,500 ÷ 0.6 = 2,500 
It's always sensible to show your working.
Write down the equation which links gravitational field strength, gravitational potential energy, height and mass. [1 mark]
gpe = mass × gravitational field strength × height or Ep = mgh 
You will have to remember this equation for the exam.
Sometimes recalling an equation is a simple one mark question and sometimes it is required to answer three and four mark questions successfully.
The National Grid ensures that fossil fuel power stations in the UK only produce about 33% of the total electricity they could produce when operating at a maximum output.
Suggest two reasons why. [2 marks]
Any two from:
Again, there are two marks for this question so you must be able to give two points. You should also show that you have given reasons to explain why.