Question

A real image, 1/5th the size of Object is formed at a distance of 18cm from lens,What is the nature of lens and ?​

Answer 1

Answer:

m=-v/u

⟹− 1/5

=−( -18/u )

⟹u=−(5×18)=−90cm

Applying the lens formula,

1/f= 1/v + 1/u

⟹1/f = 1/−18+1/-90

⟹ 1/f=-5-1/90

⟹f=−15cm

Since focal length is negative, therefore it is a concave mirror.

Answer 2

Explanation:

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