An object of size 2cm is placed in front of a concave mirror of focal length 20cm if the image formed at 30cm behind the mirror find the position of the object and height of image.
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An object of size 2cm is placed in front of a concave mirror of focal length 20cm if the image formed at 30cm behind the mirror find the
Verified answer
Answer:
[4pt]
∴v=−30 cm
Thus, screen should be placed 30 cm in front of the mirror (Centre of curvature) to obtain the real image.
Now,
Height of object, h
1
=2 cm
Magnification, m=
h
1
h
2
=−
u
v
Putting values of v and u:
Magnification m=
2 cm
h
2
=−
−30 cm
−30 cm
⇒
2 cm
h
2
=−1
[4pt];
⇒h
2
=−1×2 cm=−2 cm
Thus, the height of the image is 2 cm and the negative sign means the image is inverted.
Thus real, inverted image of size same as that of object is formed.
The diagram shows image formation.