Student Login

Home›Chapters›Ray Optics PYQs›Optical Instruments & the Eye›Question 40

NEET 2016 (Phase 1) · Optical Instruments & the Eye

Optical Instruments & the Eye question from NEET 2016 (Phase 1)

Q40NEET 2016 · PHASE 1Medium

Optical Instruments & the Eye

A astronomical telescope has objective and eyepiece of focal lengths 40 cm and 4 cm respectively. To view an object 200 cm away from the objective, the lenses must be separated by a distance

Show answer and solution

Answer: (b)

Objective: $\dfrac{1}{v} = \dfrac{1}{40} - \dfrac{1}{200} = \dfrac{4}{200} \Rightarrow v = 50$ cm.
Normal adjustment: this image lies at the eyepiece focus, $f_e = 4$ cm.
Separation $= 50 + 4 = 54$ cm.
So the answer is (b) 54.0 cm.

Report a mistake

More questions on Optical Instruments & the Eye

A telescope has an objective lens of focal length 150 cm and an eyepiece of focal length…JEE Main 2015 (10 Apr, Shift 1)
In an astronomical telescope in normal adjustment a straight black line of length L is…NEET 2015 (AIPMT)
If the focal length of objective lens is increased then magnifying power ofNEET 2014 (AIPMT)
In a compound microscope the focal length of objective lens is 1.2 cm and focal length of…JEE Main 2014 (11 Apr, Shift 1)
The focal lengths of objective lens and eye lens of a Galilean Telescope are respectively…JEE Main 2014 (9 Apr, Shift 1)
This question has Statement-1 and Statement-2. Of the four choices given after the…JEE Main 2013 (23 Apr, Shift 1)
For a normal eye, the cornea of eye provides a converging power of 40 D and the least…NEET 2013
The focal length of the objective and the eyepiece of a telescope are 50 cm and 5 cm…JEE Main 2013 (22 Apr, Shift 1)