1. Tardigrade
  2. Question
  3. Physics
  4. An astronomical telescope has objective and eyepiece of focal lengths 40cm and 4cm respectively. To view an object 200cm away from the objective, at what distance the lenses must be separated (in cm )?

Question Error Report

Thank you for reporting, we will resolve it shortly

Back to Question

Q. An astronomical telescope has objective and eyepiece of focal lengths $40cm$ and $4cm$ respectively. To view an object $200cm$ away from the objective, at what distance the lenses must be separated (in $cm$ )?

NTA AbhyasNTA Abhyas 2022

Solution:

$\frac{1}{V}-\frac{1}{- 200}=\frac{1}{40}$
$\frac{1}{V}=\frac{5}{5}\frac{1}{40}-\frac{1}{200}$
$=\frac{5}{200}-\frac{1}{200}$
Solution
$\frac{1}{V}=\frac{4}{200}=\frac{1}{50}$
$V=50$
$\therefore d=50+4=54 \, cm$