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The ratio of resolving powers of an optical microscope for two wavelengths λ₁=4000 A and λ₂=6000 A is

Asked in NEET 2017 · Resolving power and limits of ray optics

Answer: (3) 3:2

Step-by-step solution

Given: λ₁=4000 A and λ₂=6000 A, same microscope.

Idea: resolving power is the reciprocal of the smallest resolvable separation, and that separation is proportional to the wavelength.

RP∝1/λ.

(RP₁)/(RP₂)=(λ₂)/(λ₁)=(6000)/(4000).

=3/2.

The shorter wavelength resolves better, which is why blue light sharpens a microscope image.

Why the other options are wrong

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