Question

A linear object of height 5cm is placed in front of a plane mirror at a distance of 15cm from the mirror. Find the position and height of the image formed​

Answer 1

Given :

• height of object = 5 cm

• Distance of object from plane mirror = 15 cm

To find :

• position and height of the image.

Concept used :

• In a plane mirror distance between the object from the mirror is equal to distance between the image obtained.

• The size of the image ( formed by plane mirror) is the same as the size of the object.

Solution :

Now we know that :- In a plane mirror distance between the object from the mirror is equal to distance between the image obtained.

Therefore , image is at 15 cm from the mirror ( to the opposite side of object )

Also , The size of the image ( formed by plane mirror) is the same as the size of the object.

Therefore , image is of size 5 cm.

Explanation of diagram ( refer attachment ) :-

1. A linear object AB of height 5cm is placed in front of a plane mirror at a distance of 15cm from the plane mirror FE.
2. After reflection from the mirror an image of same height (5cm )is obtained. Position of image is opposite to the object but distance is same from the mirror i.e 15cm.

Answer :

• Size of image = 5 cm

• position = 15 cm from the mirror

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Properties of image formed by a plane mirror :-

• The image formed is always erect.

• The image obtained by plane mirror is laterally inverted.

• The size of the image is equal to the size of the object.

• The image obtained is virtual.

• In a plane mirror distance between the object from the mirror is equal to distance between the image obtained.

Laws of Reflection :-

• The angle of incidence is equal to the angle of reflection .

• The incident ray, the normal at the point, and the reflected ray lie on the same plane.

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