Physics 5054 · O Level · Thin lenses

Thin lenses — practice question

A parallel beam of light moving through air falls on a glass lens. As shown in Fig. 8.1, the beam is at right angles to the lens. The dashed line P shows where the lens is placed. The lens centre is marked by dot C.
(a(i))[1]

This lens is a diverging lens. On Fig. 8.1, show the lens shape by drawing its outline around dashed line P.

(a(ii))[2]

Show the route followed by each light ray after it has passed through the lens.

(b(i))[2]

Fig. 8.2 shows a simplified short-sighted eye. Light from a distant object enters the eye after striking the eye lens. On Fig. 8.2, extend the three rays in the eye until they reach the back of the eye.

(b(ii))[1]

State how the image of a distant object seen by a normal eye is different from the image seen by the short-sighted eye.

(b(iii))[1]

Explain how a diverging lens corrects the vision of a short-sighted eye viewing a distant object.

(c(i))[4]

The focal length of the diverging lens is 4.0 cm. An object of height 3.5 cm stands 6.0 cm from the centre of the lens. By drawing on Fig. 8.3, find where the image I of object O is formed. Draw image I and label it I.

(c(ii))[1]

State whether the image formed is real or virtual.

(c(iii))[1]

On the grid in Fig. 8.3, write an E in a position from which the image can be seen by an eye.

(c(iv))[2]

Determine the linear magnification produced.

Worked solution & mark scheme

This 15-mark question has a full step-by-step worked solution and mark scheme. One marking point: a vertical biconcave lens outline on P

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