BSc Nursing GNM 2019 Solved Paper

Smallest angle that can be resolved by telescope is given by
dθ=‌

1.22λ

D

Smallest angle that can be resolved by human eye is given by
dθ′=‌

1.22λ

De

where, De is the aperture of human eye, therefore the telescopemust have a minimum magnifying power which must be such that if an object subtend an angle dθ at its objective, the final image produced must subtend an angle dθ′ at the human eye.
∴ Minimum magnifying power is given by
M=‌

dθ′

dθ

=‌

D

De

⇒M‌‌=‌

100cm

0.2cm

‌‌=500‌‌‌‌[∵D=100cm‌ and ‌
De=0.2cm‌ (given) ‌]