Question

Where is the image located when an object is 60 cm from a convex mirror with a focal length of20 cm?

15 cm behind
30 cm behind
60 cm behind
15 cm in front

Answer 1

Answer on Question #52752-Physics-Optics

Where is the image located when an object is 60 cm from a convex mirror with a focal length of 20 cm?

a. 15 cm behind

b. 30 cm behind

c. 60 cm behind

d. 15 cm in front

Solution

Here $u = -ve, f = +ve$.

$$\frac{1}{u} + \frac{1}{v} = \frac{1}{f}$$ $$\frac{1}{-60} + \frac{1}{v} = \frac{1}{20} \rightarrow v = 15\,\text{cm}$$

The $+ve$ sign indicates that image is virtual and behind the mirror.

Answer: a. 15 cm behind.

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