Question

a concave lines of focal lines 20 cm from an image at a distance of 10 cm from lens what is the distance of object from the lions? also draw diagram​

Answer 1

Given :-

Focal length = -20 cm

Image distance = -10 cm

To Find :-

The distance of object from the lens.

Solution :-

We know that,

• f = Focal length
• u = Distance between mirror and object
• m = Magnification
• v = Distance between mirror and image

Using the formula,

$\underline{\boxed{\sf Mirror \ formula=\dfrac{1}{v}+\dfrac{1}{u}=\dfrac{1}{f} }}$

Given that,

Focal length (f) = -20 cm

Image distance (v) = -10 cm

Substituting their values,

-1/u - 1/10 = -1/20

-1/u = -1/20 + 1/10

-1/u = 1/20

u = -20 cm

Therefore, the object is placed at a distance of 20 cm from the concave lens.