Question

A lens of a focal length 20 cm is used to produce a ten times magnified image of a film slide on a screen. How far must the slide be placed from the lens?

Answer 1

Answer:

Explanation:

f = 20 cm

m = - 10 (Image is real)

u =?

m = v/u = -10

v = -10u

Lens formula: 1/v – 1/u = 1/f

1/-10u – 1/u = 1/20

(-1 – 10)/10u = 1/20

-11/10u = 1/20

u = -22 cm

v = -10 × -22 = 220 cm

Answer 2

Answer:

220cm

Explanation:

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