Optics Question 416
Question: The focal lengths of the objective and eye-piece of a telescope are respectively 100 cm and 2 cm. The moon subtends an angle of $ {{0.5}^{o}} $ at the eye. If it is looked through the telescope, the angle subtended by the moon’s image will be
[MP PMT 2000; DCE 2003]
Options:
A) $ 100^{o} $
B) $ 50^{o} $
C) $ 25^{o} $
D) $ 10^{o} $
Show Answer
Answer:
Correct Answer: C
Solution:
$ \frac{\beta }{\alpha }=\frac{f _{o}}{f _{e}}\Rightarrow \frac{\beta }{{{0.5}^{o}}}=\frac{100}{2}\Rightarrow \beta =25^{o} $
