Q25. The objective diameter of an astronomical telescope is doubled without changing the focal lengths or the wavelength. Under diffraction-limited operation, which are correct? (Select all correct options.)
Select all that apply

Question

Q25. The objective diameter of an astronomical telescope is doubled without changing the focal lengths or the wavelength. Under diffraction-limited operation, which are correct? (Select all correct options.)

Select all that apply

G1 Physics · Accepted Answer

This is MULTIPLE CORRECT. Let original objective diameter be d; new diameter is 2d. A: TRUE. Light-gathering ability is proportional to area πd²/4, so new/old = (2d/d)² = 4. B: TRUE. Rayleigh angular limit θₘᵢₙ = 1.22λ/d. New limit = 1.22λ/(2d) = θₘᵢₙ/2. C: TRUE. For fixed telescope focal lengths, |M| = fₒ/fₑ and does not involve objective diameter. D: FALSE. Doubling aperture does not double angular magnification; it mainly improves collection and diffraction-limited resolution. FINAL ANSWER:…