Question

An object of height 7cm is kept at a distance front of a concave mirror. the focal length of the mirror is 15cm. At what distance from the mirror
Should a screen be kept soas to get a clear image?
will be the size and nature of the image?​

Answer 1

Answer:

Given object height (h

o

)=7cm

Object distance (u)=−25cm

Foeal length (f)=−15cm

Using mirror formula,

u

1

+

v

1

=

f

1

; v= distance of image

⇒

v

1

=

25

1

−

15

1

∴

v

1

=

75

2.5

⇒v=−37.5cm

The screen should be placed at 37.5cm from the pole of the mirror and infront of the mirror.

Magnification (m)=

h

o

h

i

=−

4

v

⇒

h

o

h

i

=−(

−25

−37.5

)=−1.5

∴h

i

=−(1.5×7)cm=−10.5cm

So, size of image is 10.5cm and it will be real, inverted and magnified.