Question

Where must an object be placed to have a magnification of 2.30 in each of the following cases, if it can possibly be produced?

(a) a converging lens of focal length 11.9 cm

6.726 cm17.074 cm    2.493 cm0.251 cm0.638 cm2.107 cmA converging lens cannot produce an image with this magnification.

(b) a diverging lens of focal length 11.9 cm

6.726 cm17.074 cm    2.493 cm0.251 cm0.638 cm2.107 cmA diverging lens cannot produce an image with this magnification.

Answer 1

here,

a)

let the object distance and image distance be do and di

magnification , m = 2.3 = -di/do ...(1)

focal length , f = 11.9 cm

using the lens formula

1/f = 1/di + 1/do

1/11.9 = 1/di + 1/do ...(2)

from (1) and (2)

do = 6.726 cm

the object distance is 6.726 cm

b)

let the object distance and image distance be do and di

magnification , m = 2.3 = -di/do ...(1)

focal length , f = - 11.9 cm

using the lens formula

1/f = 1/di + 1/do

- 1/11.9 = 1/di + 1/do ...(2)

from (1) and (2)

do = - 6.73 cm

so, A diverging lens cannot produce an image with this magnification.