Diameter of the objective lens of a telescope is 250 cm... | Wave Optics

JEE MAIN 2019

09-04-2019 S2

Question

Diameter of the objective lens of a telescope is 250 cm. For light of wavelength 600 nm. coming from a distant object, the limit of resolution of the telescope is close to :

Select the correct option:

$1.5 \times 10^{-7} \mathrm{rad}$

$3.0 \times 10^{-7} \mathrm{rad}$

$2.0 \times 10^{-7} \mathrm{rad}$

$4.5 \times 10^{-7} \mathrm{rad}$

✓ Correct! Well done.

✗ Incorrect. Try again or view the solution.

Solution

$\begin{aligned} & \theta=\frac{1.22 \lambda}{D} \\ & \Rightarrow \quad \theta=\frac{1.22 \times 600 \times 10^{-9}}{250} \times 100=2.92 \times 10^{-7} \\ & \Rightarrow \quad \theta=3 \times 10^{-7} \mathrm{rad}\end{aligned}$

Question Tags

JEE Main

Physics

Medium

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