Question

Write 2 uses of a concave mirror. Write a short note on dispersion of light.

Answer 1

The spherical mirror with inward curved reflection surface is called concave mirror.
1.concave mirror are commonly used in torchs, search lights and vehicle headlights to get powerful parallel beam of light.
2. dentist use concave mirror to see large image of the teeth.
3. large concave Mirrors are used to concentrate sunlight to produce heat in solar furnaces.
**now let discuss about dispersion of light.
the phenomenon of splitting white light into seven colours when it passes through a glass prism is called Dispersion of white light.
cause of dispersion:
each colour has its own wavelength the wavelength of red colour is the longest and the wavelength of violet colour is the shortest

speed of light or colour depends upon the wavelength
if wavelength of a colour is large the speed of colour is also large.
thus, each colour of light travels with different speed in a given medium.

Answer 2

Why don't u use the text book of NCERT ALWAYS PREFER IT AND ITS AN ANSWER GIVEN QUITE PROPERLY THERE.. but see the logic is that concave mirror produces the image at infinity and beyond c when kept at focus or just between foucs and centre of curvature so.. we get powerfully beams of light which can be used to get larger image. so it is used IN

1) HEADLIGHTS OF CARS

2) BY DENTISTS TO SEE TEETHS

LARGER MIRRORS ARE ALSO USED FOR SOLAR FURNACES TO CONCENTRATE SUNLIGHT..

DISPERSION OF LIGHT..

WHEN THE REFRACTION OF LIGHT TAKES PLACE THROUGH THE GLASS PRISM IT GETS SPLIT INTO BANDS OF COLOUR OF VIBGYOR THIS BAND IS CALLED ITS SPECTRUM THE SPLIT OF THESE LIGHTS IS THE DISPERSION DRAW THE FIGURE ON PG 193 FOR 3OR 4 MARKS..