Question

A point light source is placed in front of a convex mirror at al
distance of 40 cm. The focal length of the mirror is 40 cm
Find the position of the image.​

Answer 1

Answer:

Image distance is 20 cm

Answer 2

Answer:Object distance (O) = - 40 cm

Focal length (f) = 40 cm (convex)

Let the image distance be 'v' then

     

1

u

+

1

v

=

1

f

Or,  

1

−

40

+

1

v

=

1

40

Or,

1

v

=

1

40

+

1

40

=

1

+

1

40

Or,

1

v

=

2

40

Or, v = 20 cm

∴ The image is 20 cm back of the mirror.

Explanation: