JEE Main 2015PhysicsRay OpticsMediumMCQ

JEE Main 2015 — Ray Optics Question with Solution

JEE Main 2015 (10 Apr Online)

Question

A telescope has an objective lens of focal length 150 cm and an eyepiece of focal length 5 cm. If a 50 m tall tower at a distance of 1 km is observed through this telescope in a normal setting, the angle formed by the image of the tower is θ, then θ is close to

Choose an option

Show full solutionCorrect option: D
Correct answer
D86°

Step-by-step explanation

Angular magnification of a telescope in normal adjustment is

m=βα=f0fe⇒β=f0feα



According to the question

α=yx=501000=120

⇒α=120

⇒β=1505×120=32 rad

=32×180°3.14=86°

Practice this on the real CBT interface

Solve this JEE Main question (and the rest of the Ray Optics chapter) on PrepSharp's TCS iON-style CBT player — with timer, bookmarks and session analytics.

Solve interactively →

About this question

This is a previous-year question from JEE Main 2015, covering the Ray Optics chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.