Question

An astronomical telescope which contain objective and eyepiece lens of focal length $f_0$ and $f_e$ respectively. The aperture of objective lens is $d$ and wavelength used is $\lambda$. Select incorrect option.

• A. Resolving power does not depend on $f_0$
• B. Resolving power decreases on increasing $\lambda$
• C. Resolving power depends on diameter of aperture of objective
• D. Resolving power increases on increasing value of $f_e$

Answer 1

Answer: (D)

Resolving power increases on increasing value of $f_e$

Answer 2

The resolving power (RP) of an astronomical telescope is given by the formula: $RP = \frac{d}{1.22\lambda}$ where $d$ is the diameter of the objective lens aperture and $\lambda$ is the wavelength of light. This formula shows that RP is directly proportional to $d$ and inversely proportional to $\lambda$. It does not depend on $f_0$ or $f_e$. Therefore, options A, B, and C are correct statements, while option D is incorrect.