Question

Convex lens forms two times virtual image of an object placed that 20cm in front of it.Calculate focal length and position of the image​

Answer 1

Explanation:

Here,

Image distance=v=20cm,

Object distance=u=−30cm,

Lens equation is given by,

v1−u1=f1,

putting the values we get,

201−−301=f1,

∴f=12cm

∴ Focal length of convex lens=f=12cm