Question

An object is placed 40 cm in front of a concave mirror and an image of same size as that of the object is from what is the focal length of the Mirror?

Answer 1

Answer:

here,

the distance of the object (u)= (-40)cm

magnification= (-1)

we found,

m= -v/u

=> -1=-v/-40

=>v= -40cm

we know that

when the distance of the object and image are equal than the image formed in the centre of curvature.

therefore,

C= -40cm

f=C/2

=-20cm.

Explanation:

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