The objective lens of a compound microscope produces magnification of 10 . In order to get an overall magnification of 100 when image is formed at 25 cm from the eye, the focal length of the eye lens should be

Question

The objective lens of a compound microscope produces magnification of 10 . In order to get an overall magnification of 100 when image is formed at 25 cm from the eye, the focal length of the eye lens should be (A) 4 cm (B) 10 cm (C) (25/9) cm (D) 9 cm

Tardigrade Admin · Accepted Answer

m=mo × me m=mo ×(1+(D/fe)) ⇒ 100=10 ×(1+(25/fe)) ⇒ fe=(25/9) cm

Q. The objective lens of a compound microscope produces magnification of $10.$ In order to get an overall magnification of $100$ when image is formed at $25 c m$ from the eye, the focal length of the eye lens should be

4 cm

10 cm

$\frac{25}{9} c m$

9 cm

$m = m_{o} \times m_{e}$
$m = m_{o} \times (1 + \frac{D}{f _{e}})$
$\Rightarrow 100 = 10 \times (1 + \frac{25}{f _{e}})$
$\Rightarrow f_{e} = \frac{25}{9} c m$

Q. The objective lens of a compound microscope produces magnification of 10. In order to get an overall magnification of 100 when image is formed at 25cm from the eye, the focal length of the eye lens should be