Question

A 2 cm candle is placed in front of convex mirror having focal length 15 cm . Image is formed 10 cm away from the mirror . The height of the image ?
a) 2/3
b) 1/3
c) 1
d) 2
With explanation and no spam answers otherwise I'll report​

Answer 1

Given:

A 2 cm candle is placed in front of convex mirror having focal length 15 cm . Image is formed 10 cm away from the mirror.

To find:

Height of image?

Calculation:

Applying Mirror Formula:

$\dfrac{1}{f} = \dfrac{1}{v} + \dfrac{1}{u}$

$\implies \dfrac{1}{15} = \dfrac{1}{10} + \dfrac{1}{u}$

$\implies \dfrac{1}{u} = \dfrac{1}{15} - \dfrac{1}{10}$

$\implies \dfrac{1}{u} = \dfrac{2 - 3}{30}$

$\implies \dfrac{1}{u} = \dfrac{ - 1}{30}$

$\implies \: u = - 30 \: cm$

Now, height of image :

$\dfrac{h_{i}}{h_{o}} = - \dfrac{v}{u}$

$\implies \dfrac{h_{i}}{2} = - \dfrac{15}{ ( - 30)}$

$\implies h_{i} = 1 \: cm$

So, height of image is 1 cm.