Question

answer the following question
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Answer 1

Answer:

let u= - infinity

v= -10m

by using lens formula

1/f=1/v -1/u

1/f = 1/-10 -1/0

1/f =1/-10

f= -10

Answer 2

Answer:

1/v - 1/u = 1/f

Concave lens use here

u - infinite

v - -10m

1/f = -1/10m

f - -10m