JEE Main 2026 · 8 Apr · Shift 2 · Physics Q47

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PhysicsInteger+4 / -1Question 47 of 75

Some distant star is to be observed by some telescope of diameter of objective lens $a$ , at an angular resolution of $3.0\times10^{-7}$ radian. If the wavelength of light from the star reaching the telescope is 500 nm, the minimum diameter of the objective lens of the telescope is ________ cm. (nearest interger)

Your answer

Answer and worked solution

Official answer: 203

Rayleigh criterion.
$D=\frac{1.22\lambda}\theta=\frac{1.22\times5\times10^{-7}}{3\times10^{-7}}=2.03\text{ m}\approx203\text{ cm}.$

Answer: 203

Topics:Resolving power

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JEE Main 2026 · 8 Apr · Shift 2, Physics question 47