Question

What is focal length of plane mirror and mention the nature of image formed by plane mirror?

Answer 1

Hey mate here is your answer》》

Plane mirrors are the only type of mirror for which a real object always produces an image that is virtual, erect and of the same size as the object. Virtual objects produce real images, however. The focal length of a plane mirror is infinity; its optical power is zero.

Because in plane mirror,the distance of object "a" from the mirror and the distance from image “b” to the mirror are equal.

so by using formula,

1/f=1/a+1/b

We get,

1/f=1/a -1/b (bcz p=q)and (b is taken as negative bcoz image of plane mirror is virtual.

so,

1/f=0,

f=1/0

and any thing divided by zero is infinity.

Hope this answer will help you..《《

Answer 2

A plane mirror will always form a virtual image. Such images are formed by light rays from the object incident on the mirror and reflected by it. These rays do not intersect after reflection. They appear to have come from behind the mirror. They do not actually originate behind the mirror. The image that appears to be formed behind the mirror can not be captured on a screen nor it can be recorded.

This image is laterally reversed, the left and the right appear to be interchanged. It is also erect, the top is top and the bottom is bottom.

Its distance from the mirror is same as the distance of the object from the mirror.

If an object is moving at some speed, its image in a plane mirror appears to move at twice the speed.

This is my answer, if it helps you:)