Question

An object at a distance of 30 cm from a concave mirror gets its image at the same point. The focal length of the mirror is

Answer 1

As object and image are located at the same point and in front of concave mirror then we take u = +30 cm and v = + 30 cm. ... Thus, the focal length of mirror is 15 cm.

→mirror formula←

1/f=1/v+1/u

for concave mirror f is in -ve

1/-20=1/v-1/30

1/v=-1/20+1/30

1/v=-3+2/60

1/v=-1/60

v=-60 cm

Answer 2

Answer:

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