Question

A concave lens of focal length 15cm forms an image 10cm from the lens.
How far is the object placed from the lens ? Draw the ray diagram​

Answer 1

Explanation:

f = -15 cm

v = 10cm

u = ?

lens formula = 1/f = 1/v-1/u

1/-15 = 1/10 -1/u

1/-15 -1/10 = 1/u

-2-3 / 30 = 1/u

u = 30/ -5

u = -6

Answer 2

Answer:

Explanation:

e= 30