Question

If an object of height 10cm is placed at a distance of 36cm in front of a concave lens of focal length 12cm. The magnification will be ?

Answer 1

Object distance u=−36 cm

Focal length of concave mirror f=−12 cm

Using mirror formula :

v

1

+

u

1

=

f

1

Or

v

1

+

−36

1

=

−12

1

⟹ v=−18 cm,

Since image position is negative, i.e. image is on the same side of object, which is real space, therefore the image is real.

Step2: Finding Height using Magnification

Magnification

h

o

h

i

=

u

−v

Or

10

h

i

=

−12

−(−18)

⟹ h

i

=−15 cm

Negative height implies that the image is inverted.

Hence, a real and inverted image of height 15 cm is formed at a distance of 18 cm in front of the mirror.

Answer 2

qadefcbhuknbcfyiok na gswrrfcvb ho o JB v saefvvbhiiokb