Question

An object is placed at a distance of 10 cm from a concave mirror. If its image is observed at 30 cm from the mirror, what is the focal length of the mirror?

Answer 1

Answer:

7.5cm

Explanation:

use formula, 1/v + 1/u = 1/f

here

V = -30cm

u = -10cm

Therefore

1/f = -1/30 - 1/10

ie f = - 7.5cm

Answer 2

m = 3

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