Q135 / 150 · MHT CET 2026 (20 April Shift 2) · Physics
To improve the resolving power of a compound microscope we should
- Adecrease the diameter of the objective lens.
- Bdecrease the focal length of the eye-piece.
- Correct answerCincrease the refractive index of the medium between the object and objective lens.
- Dincrease the wavelength of light.
Solution
The resolving power of a compound microscope is given by the formula:
$\text{Resolving Power} = \dfrac{2 \mu \sin \theta}{\lambda}$
where $\mu$ is the refractive index of the medium between the object and the objective lens, $\theta$ is the half-angle of the cone of light from the object to the objective lens, and $\lambda$ is the wavelength of light used.
To improve or increase the resolving power, one can:
1. Increase the refractive index $\mu$ of the medium.
2. Increase the angle $\theta$ (by increasing the diameter of the objective lens).
3. Decrease the wavelength $\lambda$ of the light used.
Therefore, increasing the refractive index of the medium between the object and the objective lens will improve the resolving power.
Answer: increase the refractive index of the medium between the object and objective lens.
$\text{Resolving Power} = \dfrac{2 \mu \sin \theta}{\lambda}$
where $\mu$ is the refractive index of the medium between the object and the objective lens, $\theta$ is the half-angle of the cone of light from the object to the objective lens, and $\lambda$ is the wavelength of light used.
To improve or increase the resolving power, one can:
1. Increase the refractive index $\mu$ of the medium.
2. Increase the angle $\theta$ (by increasing the diameter of the objective lens).
3. Decrease the wavelength $\lambda$ of the light used.
Therefore, increasing the refractive index of the medium between the object and the objective lens will improve the resolving power.
Answer: increase the refractive index of the medium between the object and objective lens.
Hence, the correct answer is option: 'C'.