# Light and the EM spectrum - One and two mark questions

One to two mark questions will start with command words such as 'describe' or 'explain'. Some command words are easy to understand such as:

• 'calculate' or 'determine' for maths questions
• 'complete' to fill in a gap in a table or graph
• 'state what is meant by' to give the meaning of an important term
• 'comment on' where you use your knowledge in an unfamiliar situation

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.

Edexcel questions courtesy of Pearson Education Ltd.

## Sample question 1 - Higher

Question

The picture shows a person checking that a banknote is genuine. They are using a lamp which emits radiation which is part of the electromagnetic spectrum.

Explain how two different electromagnetic radiations enable the man to check the banknote. [2 marks]

The banknote absorbs UV light and re-emits visible light.

As the question is for two marks, make sure you mention at least two different types of electromagnetic waves.

## Sample question 2 - Foundation and Higher

Question

Describe how the power of a lens is related to its shape.

You may draw labelled diagrams if it helps your answer. [2 marks]

A lens that is more curved has a larger power.

You could also draw a clearly labelled diagram like the one below: