Question

where should an object be placed from a converging lens of focal length 15cm, so as to obtain a real image of same size as that of the object?

Answer 1

The object should be placed between 15cm and 30 cm( Between f and 2f)  from the converging lens to obtain a real and magnified image.

Answer 2

Dear Student,

● Answer -

at 30 cm

◆ Explanation -

According to lens formula,

1/f = 1/v - 1/u

For real image of same size, v = -u.

1/f = 1/-u - 1/u

1/f = -2/u

u = -2f

u = -2 × 15

u = -30 cm

Hence, object should be placed 30 cm (which is at principal focus) in front of lens to obtain real image of same size.

Thanks dear. Hope this helps you...