Question

An object whose size is 7.0 cm is placed in front
of a concave mirror whose focal length is 18 cm.
At what distance from the mirror should a screen
be placed so as to get the sharp image of the
object. Find size and nature of the image.​

Answer 1

Answer:

Given:

size of object, o=+7cm

distance of object ,u=−27cm

focal length of concave mirror, f=−18cm

let us take size of image=I

so, mirror formula is

v

1

+

u

1

=

f

1

so, putting values of u and v,

v

1

=

−18

1

−

−27

1

v

1

=

−54

1

v=−54cm

so, image is formed on object side only.

magnification,

m=

u

−v

=

o

I

m=−

−27

−54

=

7

I

I=−14cm

so, image is double in size to that of object.

Nature: real, inverted and magnified image.