Question

An object is placed 60 cm in front of a concave spherical mirror whose focal length is 40cm. which of the following best described the image?
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Answer 1

Explanation:

Focal length of a concave mirror is negative.

Given : f=−40 cm u=−60 cm

Using

v

1

+

u

1

=

f

1

∴

v

1

+

−60

1

=

−40

1

⟹v=−120 cm

Thus the image is at a distance of 120 cm from the mirror.

Also as the image distance comes out to be negative, this implies that the image is formed in front of concave mirror and hence the image is real.

Answer 2

Answer:

Focal length of a concave mirror is negative.

Given : f=−40 cm u=−60 cm

Using

v

1

+

u

1

=

f

1

∴

v

1

+

−60

1

=

−40

1

⟹v=−120 cm

Thus the image is at a distance of 120 cm from the mirror.

Also as the image distance comes out to be negative, this implies that the image is formed in front of concave mirror and hence the image is real.

Hope it's will help you