Question

what is the position of the image when an object is placed at a distance of 20 cm grom a concave mirror of focal length 20 cm​

Answer 1

Answer:

Object position (u) = - 20 cm (-ve sign due to position of object opposite to direction of incident ray)

Focal length (f) = -20 cm (focal length of concave mirror is always negative)

Mirror formula

1/f = 1/u + 1/v

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

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

1/v = 10

v = infinite ( not defined)

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