Q1. Sunita puts on a pair of special glasses as shown below. The glasses have coloured filters in them.

(a) Sunita looks at a lamp through the green filter. The lamp gives out white light, but appears to be green. Explain how this is possible.

2 marks

The green filter allows green light to pass though it and absorbs all other colours. Sunita therefore only sees the green light from the lamp.

(b) Sunita looks at a red lamp.

(i) What colour will the lamp appear to Sunita, if she looks at it through the red filter? Explain your answer.

1 mark

The red filter allows red light to pass though it . Therefore the lamp appears to be red.

(ii) What colour will the lamp appear to Sunita, if she looks at it through the green filter? Explain your answer.

2 marks

The green filter only allows green light to pass though it and it will absorb all the red light. Sunita therefore sees no light coming from the lamp - it looks black.

Maximum 5 marks