Topic Menu

Cyber-chess a chess instruction site

GCSE level optics questions

Q16. The diagram shows how a concave lens forms an image of an object.

(a) Which letter on the diagram marks the position of the principal focus of the lens? B

[1 mark]

(b) Give two words to describe the image.

The image is upright, diminished and virtual (any two)

[2 marks]

(c) Calculate the magnification produced by the lens.

Magnification = size of image/size of object

Magnification = 12 squares/5 squares

Magnification = 2.4

You could have done this by using your ruler and expressing the image and object sizes in mm - but it is more straightforward to use the graph squares!

[4 marks]

(d) What happens to the size of the image as the object is moved further away from the lens?

The image gets smaller/diminishes/decreases in size

[1 mark]

(Total 8 marks)