The focal lengths of the objective and eye lenses of a telescope are respectively 200 cm and 5 cm . The maximum magnifying power of the telescope will be

Options

A. `-100`
B. `-60`
C. `-48`
D. `- 40`

Answer

C

Explanation

Magnifying power, `M = (f _(0))/( f _(e)) (1 + (f _(e))/(d))`
Lest distance of distinct vision,
`d = 25 cm `
`M =- (200)/(5) (1 + (5)/(25)) =- 40 (1 + (1)/(5))`
`= - 40 ((6)/(5)) =- 48 cm.`