Question

an object is placed with a 10cm distance in the front of concave mirror if focal length 5cm.Find the distance of image

Answer 1

U = -10 cm
F= -5cm
V= ?
1/F= 1/v+1/u
I/-5= 1/v + 1/-10
1/v= 1/5 + 1/-10
= -3+2/10 = -1/10
Therefore, v = -10cm.

Answer 2

Given:
u = -10 cm
f = -5 cm
By mirror formula, we have
$\frac{1}{f} = \frac{1}{u} + \frac{1}{v}$
$\frac{1}{v} = \frac{1}{f} - \frac{1}{u}$
$\frac{1}{v} = \frac{1}{ - 5} - \frac{1}{ - 10}$
$\frac{1}{v} = \frac{1}{ - 5} + \frac{1}{10}$
$\frac{1}{v} = \frac{ - 1}{10}$
v = -10
Hence distance of image from the mirror is -10cm
- sign indicates image formed is real and inverted and is infront of the mirror