Question

Define-
1 real image
2 virtual image
3 concave mirror
4 concave mirror
5Dispersion
6 Refraction

Answer 1

Real Images

A real image is that image which is formed when the light rays coming from an object actually meet each other after reflection or refraction. A real image can be obtained on the screen. The real image is always inverted. The common example of real image is the image formed on the cinema screen.

Virtual Image

A virtual image is that image which is formed when the light rays coming from an object do not actually meet, but appear to meet when produced backwards. These images cannot be obtained on the screen. The virtual image is always erect. The common example of virtual image is the image formed in the mirror when we stand in front of that mirror.

CONCAVE MIRROR

Concave mirror refers to the mirror whose reflecting surface is towards the center of curvature.
Centre of curvature Lies in front of the mirror
Converging type mirror
Real or virtual image is formed.
Reflectors in projectors, searchlights etc.

CONVEX MIRROR

Convex mirror implies the mirror whose reflecting surface is away from the center of curvature.
Center of curvature Lies behind the mirror
Diverging type mirror
Virtual image is formed.
Rear view mirrors in cars and bikes.(example)

Dispersion

In Physics, 'dispersion' is the property by which light is spread out according to its color as it passes through an object. For example, when you shine a white light into a , all of the different colors of light are bent different amounts, so they spread out and make a rainbow. This works because of the fact that different colors of light actually have different wavelengths. (The wavelength is the distance between the peaks in the wave.) Light interacts with the molecular structure of the prism differently depending on its wavelength. So different wavelengths of light are bent different amounts.

Definition Of Refraction

The process of bending of light ray, which is travelling from one medium to another medium.
Light ray passing from one medium (air) to another medium bends and travels.
Example: Pencil immersed in water appears as if it was bent. When you take out the pencil from the water you will not observe any bends.
The light ray coming from the object bends and comes to form an image in our eye, hence will look as if it was bent.