Question

an image 3 times the size of an object is desired to be obtained on a screen placed at a distance of 48 cm from the object what kind of lens is required and must be its focal length​

Answer 1

Answer: 3cm

Explanation:

m=v/u

3=v/u

v=3u

v+u= 48cm

3u+u = 48

u= 12cm

v= 12×3= 36cm

(1/u) + (1/v) = (1/f)

f= 3cm