Question

The powe of a lens is +5D find Nature and focal length of this lens at what distance from this lens should an object be placed so as to get its inverted image of the same size

Answer 1

It is a convex lens

So image is real and inverted

Find f by

P= 1/ f (m)

At C for same size

Answer 2

Given power of lens is 5 dioptre.

Power of lens = 1/focal length

5= 1/f

f = 1/5

f = 0.2 m

f = 20 cm.

Since, power and focal lenght of lens is in positive, so lens is Convex.