Question

An object of height 7.5 cm is placed in front of a convex mirror of radius of curvature 25cm at a distance of 40 cm .The height of the image should be

Answer 1

Answer:

Given that,

Height of object h=7.5 cm

Height of image = h’

Radius of curvature R=25 cm

Object distance u=−40 cm

Image distance = v cm

Focal length = f=

2

R

=

2

25

We know that,

v

1

+

u

1

=

f

1

v

1

=

f

1

−

u

1

v

1

=

25

2

−

40

1

v=

11

200

cm

Now, magnification is

h

h

′

=−

u

v

h

′

=h×(−

u

v

)

h

′

=−7.5×

11×(−40)

200

h

′

=3.409

h

′

=3.41cm

Hence, the height of the image is 3.41 cm