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# A converging lens of focal length 5cm is used as a magnifying glass by a man who...

### Question

A converging lens of focal length 5cm is used as a magnifying glass by a man whose nearpoint is 35cm. Calculate the magnification given by the lens

A) 8

B) 7

C) 6

D) 5

E) 4

### Explanation:

$$\frac{1}{f} = \frac{1}{u} + \frac{1}{v}$$

= $$\frac{1}{5} - \frac{1}{35} = \frac{30}{175}$$

U = $$\frac{175}{30}$$ = 5.8m

$$\frac{v}{u} = \frac{35}{5.8}$$

= 6

## Dicussion (1)

• $$\frac{1}{f} = \frac{1}{u} + \frac{1}{v}$$

= $$\frac{1}{5} - \frac{1}{35} = \frac{30}{175}$$

U = $$\frac{175}{30}$$ = 5.8m

$$\frac{v}{u} = \frac{35}{5.8}$$

= 6