Question

The eyepiece of a refracting telescope has $f=9cm$. In the normal setting, separation between objective and eyepiece is 1.8m. Find the magnification.

• A. 20
• B. 19
• C. 18
• D. 21

Answer 1

Answer: (B)

19

$L=f_0+f_e$
$1.8=f_0+0.09$
$f_0=1.71m$
$\therefore m=\frac{-f_0}{f_e}$
$=\frac{-1.71}{0.09}$
$=19$