Question

A concave mirror of focal length 20cm forms a real image at a distance of 40cm find the position of the object

Answer 1

Focal length(f) = -20cm

Image distance (v)=-40cm

From mirror formula

1/v +1/u=1/f

-1/40+1/u=-1/20

u=-40cm

Position of the object - negative (-) sign of u indicates that the object is placed in front of the mirror at a distance of 40cm.........ans✌✌✌✌

Answer 2

The position of the object is found to be 40 cm in front of the concave mirror.

Concave Mirror

A diverging mirror with a convex reflective surface bulges towards the light source is known as a convex mirror.

Mirror Formula:

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

where,

'u' is the distance of object from the pole of mirror.

'v' is the distance of image from the pole of the mirror.

'f' is the focal length of the mirror.

Given:

Negative sign shows that the distance are measured in the directions opposite to the light.

Focal length of the concave mirror is -20cm.

Image distance if found to be -40cm.

Applying mirror formula,

$\frac{1}{-20} +\frac{1}{-40} +\frac{1}{u}$

$\frac{1}{u} = \frac{1}{-40}$

Taking reciprocal, we get

u = - 40 cm.

Therefore, the distance at which object was kept was 40 cm in front of the mirror.

To know more about types of mirrors, here

https://brainly.in/question/7432106?msp_poc_exp=2

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