Question

An object is placed 20 cm from the concave mirror of focal length 10 cm, then image is formed at?
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Answer 1

hyy mate ✌️

concave mirror

u=-20

f=-10

1/f=1/v+1/u

1/-10=1/v+1/-20

1/v=1/20-1/10

1/v=1-2/20

1/v=-1/20

v=-20

image is formed 20cm from the pole in front of the lens

nature:

m=-v/u

=-(-20)/-20

=-1

so the image is real, inverted and same size image.

hope it will help you ❣️

Answer 2

$\huge \fcolorbox{black}{aqua}{solution.}$

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

$\frac{1}{ - 20} + \frac{1}{v} = \frac{1}{ - 10}$

$\frac{1}{v} = \frac{1}{20} - \frac{1}{10}$

$\frac{1}{v} = \frac{1 - 2}{20}$

$\frac{1}{v} = \frac{ - 1}{20}$

$v = - 20 \: cm$

Hence, the image is formed at the centre of the curvature of mirror.