Question

An object of height 7 cm is kept at distance 25 cm front of concave
mirror . The focal Length of the mirror is 15 cm, where should a
screen be placed to get a dear image.​

Answer 1

Answer:

Physics

An object of size (height) 7cm is placed at 25cm in front of concave mirror of focal length 15cm. At what distance from the mirror should a screen be placed, so that we can get a sharp and clear image? Find nature and size (height) of the image.

Answer

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Size of object h

o

=7cm

Size of the object h

o

=?

Focal length f=−15cm

Object distance u=−25cm

Image distance v=?

Using mirror formula,

f

1

=

v

1

+

u

1

−15

1

=

v

1

+

−25

1

v

1

=

75

−5+3

v=−37.5cm

Hence, position of image at 37.5cm infront of the mirror.

Magnification(M)=

h

o

h

i

=

u

−v

=

−25

37.5

=−1.5

h

i

=−1.5×h

O

h

i

=−1.5×7=−10.5cm

Hence,size of image is −10.5cm.

Nature of image is real,inverted and magnified.