Chapter 25, Problem 29P

To determine

(a) To determine:

The focal length of the eyepiece of the astronomical telescope.

Answer to Problem 29P

Solution:

$f_e=-3.52cm$

Explanation of Solution

Given:

$\begin{array}{l}{f}_o=88cm\\ M=25\text{X}\end{array}$

Formula used:

$M=-\frac{f_o}{f_e}$

$L=f_o+f_e$

Calculation:

Magnification of astronomical telescope is given by,

$M=-\frac{f_o}{f_e}$

Thus, focal length of the eyepiece is given by,

$\begin{array}{l}M=-\frac{f_o}{f_e}\\ f_e=-\frac{f_o}{f_e}\\ f_e=-\frac{88}{25}\\ f_e=-3.52cm\end{array}$

To determine

(b) To determine:

The overall length of the telescope.

Answer to Problem 29P

Solution:

$f_e=-3.52cm$

Explanation of Solution

Calculation:

Length of the telescope is given by,

$\begin{array}{l}L=f_o+f_e\\ L=88-3.52\\ L=84.48\text{cm}\end{array}$