Question

According to Abbe, in the formula for resolving power of microscope, the numerical aperture is represented by

• A. \( \frac{2\mu \sin \alpha}{\lambda} \)
• B. \( \frac{2 \sin \alpha}{\mu \lambda} \)
• C. \( \mu \sin \alpha \)
• D. \( \frac{\lambda}{2 \mu \sin \alpha} \)

Hint:

The numerical aperture determines the resolving power of the microscope and is proportional to the refractive index and sine of the angle of light.

Answer 1

The Correct Option is C

Step 1: Understanding the formula for resolving power.
In the formula for resolving power of a microscope, the numerical aperture \( N.A. \) is defined as: \[ N.A. = \mu \sin \alpha \] Where: - \( \mu \) is the refractive index of the medium, - \( \alpha \) is the half-angle of the cone of light entering the microscope, - \( \lambda \) is the wavelength of light. Thus, the correct answer is (C) \( \mu \sin \alpha \).