A burning candle is placed close to a thin converging lens. The candle acts as the object. A white, vertical screen is moved to a position on the other side of the lens from the candle. Fig. 6.1 is a full-scale diagram, on graph paper, of the lens and the screen. [Figure 6.1] The focal length of the lens is 2.4cm. The screen is 7.2cm from the centre of the lens. A sharply focused, inverted image of the candle is produced on the screen, as shown in Fig. 6.1.

1. (a)Define the term focal length.[1]
2. (b)(i)On Fig. 6.1, mark and label with an F, each of the two focal points (principal foci) of the lens.[1]
3. (b)(ii)The point Y is the tip of the image. On Fig. 6.1, draw a ray diagram to locate the position of the top of the object. Label this point X.[3]
4. (b)(iii)Using Fig. 6.1, determine the distance of the candle from the centre of the lens. distance = [1]

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