Free help with homework

Why join Brainly?

  • ask questions about your assignment
  • get answers with explanations
  • find similar questions

Class X Sciences

[papers from previous years]

To determine focal length of a concave mirror a student obtains
the image of a well lit distant object on a screen. To determine
the focal length of the given concave mirror he needs to measure
the distance between:

(A) mirror and the object
(B) mirror and the screen
(C) screen and the object
(D) screen and the object and also mirror and the screen



This Is a Certified Answer

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
The distance between the pole of the mirror and the image of a distant object is called the focal length of the concave mirror.

1/f = 1/ u + 1/v        for a mirror.

If the object is distant,    u >> f  or  u >> v.    so  1/u  <<  1/v  or  1/f.
so we ignore it.

  1/f = 1/v    =>    f = v.

v is the distance between the mirror and the screen.
u = distance between the mirror and the object.
f = focal length of the mirror.

1 5 1
The Brain
  • The Brain
  • Helper
Not sure about the answer?
Learn more with Brainly!
Having trouble with your homework?
Get free help!
  • 80% of questions are answered in under 10 minutes
  • Answers come with explanations, so that you can learn
  • Answer quality is ensured by our experts