Published by:
CGP EDU Academic Team
Published on: September 12, 2026
An object is at distance 
and image formed by a mirror on the same side at a distance 
, then focal length is
A
B
C
D
Text Solution
Verified by ExpertsThe correct answer is:
B
Focal length is given by
So,
To get the error in focal length, differentiate Eq. (i)
Cancelling negative signs and approximating differential change with small 
change, we get
Hence, focal length is 
taking only magnitude.
Prepare Smarter with CGP Edu
Get practice questions, solutions, and test series in one place.
Write a Review
Share your experience with this question and solution.
Commentary
Send your comment, doubt, correction, or feedback to admin.
Similar Questions
Explore conceptually related problems
The difference of speed of light in the two media A and B (v A – v B ) is 2.6 x 10 7 m/s. If the re…
A light whose electric field vectors arc completely removed by using a good Polaroid, allowed to in…
Consider a light ray travelling in air is incident into a medium of refractive index . The inciden…
A ray of ligh is incident at an angle of incidence 60° on the glass slab of refractive index . Aft…
A light ray is incident, at an incident angle , on the system of two plane mirrors M 1 and M 2 hav…
A parallel beam of light is allowed to fall on a transparent spherical globe of diameter 30 cm and …