(a) Find the position of image formed when an object of size 1 cm is placed at a distance of 15 cm from a concave mirror of focal length 10 cm.

(b) What is the focal length of a plane mirror?

Asked by Topperlearning User | 4th Jun, 2014, 01:23: PM

Expert Answer:

(a) u = -15 cm, v =?, f = -10 cm

Now putting these values in the mirror formula:

1/v + 1/u = 1/f

We get: 1/v + 1/-15 = 1/-10

1/v = 1/15 - 1/10

1/v = -1/30

v = -30 cm

So, image distance = -30 cm

Thus, the position of image is 30 cm to the left side of mirror or 30 cm in front of mirror.

(b) The focal length of the plane mirror is infinity.

Answered by  | 4th Jun, 2014, 03:23: PM

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