Question

a concave lens of focal length f produces a image 1/3 times of size of an object then find the distance of an object​

Answer 1

Answer:

magnification, m=

n

1

⇒

n

1

=

u

v

v=

n

u

from lens formula

f

1

=

v

1

−

u

1

=

u

n

−

u

1

⇒

f

1

=

u

(n−1)

⇒f=

n−1

u

u=f(n−1)