# How Far Should an Object Be Placed from the Pole of a Converging Mirror of Focal Length 20cm to Form a Real Image of the Size Exactly 1/4Th the Size of the Object? - Science

How far should an object be placed from the pole of a converging mirror of focal length 20cm to form a real image of the size exactly 1/4th the size of the object?

#### Solution

Given,
Focal length of the concave mirror (f) = 20 cm
Magnification (m) = -1/4
Using the magnification formula, we get

m=-v/u

-1/4=(-v)/u

v=u/4

Using the mirror formula, we ge

1/f=1/v+1/u

1/-20=4/u+1/u

-1/20=5/u

u=100 cmThus, the object should be placed in front of the concave mirror at a distance of 100 cm

Is there an error in this question or solution?

#### APPEARS IN

Lakhmir Singh Class 10 Physics (Science)
Chapter 4 Reflection of Light
Q 26 | Page 199