Objects and Images

 

OBJECTS:

 

    Object is a point of intersection of the incident rays.

    Objects are of two types :

 

REAL OBJECT

 

    If the incident rays are diverging from the point of intersection of incident rays then it is called a real object.

 

VIRTUAL OBJECT

 

    If the incident rays are converging from the point of intersection of incident rays then it is called a virtual object.

 

IMAGES

 

    Image is a point of intersection of the reflected or refracted rays.

    An image is formed when the light rays coming from an object actually meet (or appear to meet) at a point after reflection or refraction.

    Images are of two types

 

REAL IMAGE

 

    The real image formed due to real intersection of reflected or refracted rays. Real image can be obtained on screen.

or

    The image formed when two or more reflected or refracted rays intersect each other at a point in front of the reflecting surface (mirror) is known as a real image. It can be obtained on a screen.

    e.g. the images formed on a cinema screen are real images.

 

VIRTUAL IMAGE

 

    The virtual image formed due to apparent intersection of reflected or refracted light rays. Virtual image can’t be obtained on screen.

or

    The image formed when two or more reflected or refracted rays appear to intersect at a point behind the normal. It can’t be obtained on a screen.

    e.g. The image of our face in a plane mirror is a virtual image.

 

Note: Human eye can’t distinguish between real and virtual image because in both case rays are diverging.