Question

A concave lens of focal length 15 cm forms an image of 10 cm from the lens . How far the object placed from the lens.

Answer 1

the focal length of lens (f) =25cm
distance of image formed (v)= 10 cm
distance of object (u) = ?
we know
for a concave lens the f= -ve , v= -ve
using the lens formula

1/f=1/v-1/u
1/u = 1/v-1/f
1/u = 1 /(-10) - 1/(-15)
1/u = 1/(-10)+1/15
1/u = (-3+2)/30
1/u = -1/30
u = -30

Answer 2

Hey You ❤

Your Answer :--

Given :

Focal length of concave lens, f = - 15 cm

Image distance, v= - 10 cm

Lens Formula :

According to the lens formula,

1/v - 1/u = 1/f

1/u = 1/v - 1/f

1/u = -1/10 - ( -1/15)

1/u = -1/10 + 1/15 = -5/150

u = - 30 cm

The negative value of u indicates that the object is placed 30 cm in front of the lens.

Glad To Help :D

☑ If you like this answer than hit the like button n ho ske to follow up vi kr lena ❤