Question

What is magnification in the below diagram?

If OA = 10 cm and O’A’ = 2 cm?

• A. 8
• B. 1
• C.
• D.

Answer 1

The correct option is C

Let's take the height of the image as $h^{{}^{\prime }}$ and height of the object as $h$, image distance from the pole as $v$ and object distance from the pole as $u$.
Magnification = $\frac{heightofimage}{heightofobject}$ and magnification can also be expressed in the form of image distance from the pole and object distance from the pole.
Magnification =$\frac{-imagedistance}{objectdistance}$. So,

Magnification = $\frac{h^{{}^{\prime }}}{h}$ = $\frac{-v}{u}$

So, Magnification = $\frac{-2}{10}$ (using the sign conventions)
= $\frac{-1}{5}$. The negative sign in magnification shows that the image formed is real.