First slide

Plane mirror

Question

A plane mirror is approaching you at a speed of 10 cm/sec. You can see your image in it. At what speed will your image approach you

Moderate

A

$10 cm / \sec$
B

$5 cm / \sec$
C

$20 cm / \sec$
D

$15 cm / \sec$

Solution

Suppose at any instant, plane mirror lies at a distance x from object. Image will be formed behind the mirror at the same distance x.
When the mirror shifts towards the object by distance ‘y’ the image shifts $= x + y - (x - y) = 2 y$
So speed of image = 2 x speed of mirror

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App