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GCSE level optics questions

Q23. A door is fitted with a security lens.

The security lens allows a person to see a visitor before opening the door.

The security lens is concave.

Below is an incomplete ray diagram representing a visitor standing near the security lens.

(a) Complete the diagram above to show how an image of the visitor is formed by the concave lens.

Draw an arrow to represent the image.

Any two correct ray lines drawn from the top of the visitor, passing through the lens get you a maximum of two marks

The image drawn at the correct position and with the correct orientation gets you the third mark - but only if you got the marks for two correct rays.

[3 marks]

(b) The visitor moves further away from the security lens in the door.

How does the size of the image change?

It decreases in size

[1 mark]

(Total 4 marks)