Mirror Formula

Question 1 An object is placed at a distance of 10cm from a convex mirror of focal length 15cm.Find the position and nature of the image?

Question 2 A concave mirror produces three times magnified real image of an object placed at 10cm in front of it.Where is the image located?

Question 3 What are the sign conventions for a convex mirror?

Question 4 What are the sign conventions for concave mirror?

Question 5 Write the mirror formula for a spherical mirror?

Question 6 What do you mean by magnification produced by mirrors?

Mirror Formula

The distance of an object on principal axis from pole of spherical mirror is called object distance(u).

The distance of position of image on principal axis from pole of spherical mirror is called image distance(v).

  1       1        1

—- + —- = —-

 u        v         f


Magnification(m)

It is defined as ratio of size of image(h’) to size of object(h).

       h’

m=—–

       h

      -v

m=—–       

       u

Sign convention for reflection by spherical mirror

1)Real image

v=negative

u=negative

f=negative


2)virtual image

Convex mirror

v=positive

u=negative

f=positive

Concave mirror

u=negative 

v=positive

f=negative

Print Friendly, PDF & Email

One thought on “Mirror Formula

Leave a Reply

Your email address will not be published. Required fields are marked *