The focal length of the objective of a telescope is 60 cm. To obtain a magnification of 20 , the focal length of the eye piece should be

Question

The focal length of the objective of a telescope is 60 cm. To obtain a magnification of 20 , the focal length of the eye piece should be (A) 2 cm (B) 3 cm (C) 4 cm (D) 5 cm

Tardigrade Admin · Accepted Answer

In normal adjustment, M=(f0/fe)=20, fe=(f0/20)=(60/20)=3 cm

Q. The focal length of the objective of a telescope is $60 c m$ . To obtain a magnification of $20$ , the focal length of the eye piece should be

$2 c m$

$3 c m$

$4 c m$

$5 c m$

In normal adjustment,
$M = \frac{f _{0}}{f _{e}} = 20, f_{e} = \frac{f _{0}}{20} = \frac{60}{20} = 3 c m$

Q. The focal length of the objective of a telescope is 60cm. To obtain a magnification of 20 , the focal length of the eye piece should be

2cm

3cm

4cm

5cm