A telescope, whose objective lens has an aperture of 1 ~mm for the wavelength of light 500 Å , then limiting resolving power of the telescope is

Correct answer: D. 6.1 × 10^ -5 rad Given: Aperture of objective lens (a)=1 ~mm=1 × 10^ -3 ~m Wavelength of light (λ)=500 Å=500 × 10^ -10 ~m Limiting resolving power of telescope, d θ=(1.22 λ)/(a)= 1.22 × 500 × 10^ -10 1 × 10^ -3 =6.1 × 10^ -5 rad

AIIMS 201926 May

Exam: AIIMS
Year: 2019
Date: 26 May
Subject: Physics
Chapter: Ray Optics

AIIMS 2019 · 26 May · Physics · Ray Optics

A telescope, whose objective lens has an aperture of 1 ~mm for the...

A telescope, whose objective lens has an aperture of

1 \mathrm{~mm}

for the wavelength of light

500 Å

, then limiting resolving power of the telescope is

Options

A $2.1 \times 10^{-5} \mathrm{rad}$
B $4.1 \times 10^{-5} \mathrm{rad}$
C $5.1 \times 10^{-5} \mathrm{rad}$
D $6.1 \times 10^{-5} \mathrm{rad}$

Correct answer

D. $6.1 \times 10^{-5} \mathrm{rad}$

Step-by-step solution

Given: Aperture of objective lens

(a)=1 \mathrm{~mm}=1 \times 10^{-3} \mathrm{~m}

Wavelength of light

(\lambda)=500 Å=500 \times 10^{-10} \mathrm{~m}

Limiting resolving power of telescope,

d \theta=\frac{1.22 \lambda}{a}=\frac{1.22 \times 500 \times 10^{-10}}{1 \times 10^{-3}}=6.1 \times 10^{-5} \mathrm{rad}

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