Question

a concave mirror produces three times enlarged image of an object is 10 centimetre in front of it calculate the focal length of the mirror

Answer 1

Hello!

From the given details we have

Object distance u=10 cm.

Image distance v= 3×10=30 cm.

As it is a concave mirror, v=-30 cm.

So now we apply these to the mirror formula.

1/v+1/u=1/f

-1/30+1/10=1/f

2/30=1/f

f=15

So the focal length of the mirror is 15 cm. Hope that answered your question!