Question

the focal length of a rear view mirror in a car is 20 CM at an instance another car approaching from the back side is at a distance of 400 cm from it find the position and the relative size of image at this instance

Answer 1

it is convex mirror

f = +20cm
u = +400cm
v = ?
1/f = 1/v + 1/u
1/20 = 1/v + 1/400
1/v = 1/20 -1/400 =19/400
v =. 400cm.

size of image will be smaller than size of image

Answer 2

They form erect, virtual, and diminished images which allow the driver to view a large area in a small mirror. Similarly, safety mirrors fixed in stores can form images of a number of visitors at a time, which helps the store staff to monitor their activities.