what is laser?

Answer 1

A laser (from the acronym Light Amplification by Stimulated Emission of Radiation) is an optical source that emits photons in a coherent beam.

Answer 2

a laser is a stream of red light. It is emitted when a high voltage is applied in a gas (helium-neon mixture) encapsulated in an air free container that is no air is present inside + the gas is at a vey low pressure. Two mirrors are placed at both ends of the tube. I'll explain why later.

The high voltage excites the gas molecules, making them to emit red light.
The use of the morror is to reflect the high energy laser light produced throughout the gas to create a more intense stream of light. This light you see in a laser comes from millions of atoms of gas present in a tube.

If you wonder why only red light, not any other light colour, please do ask me again if you are interested. I'll be delighted to answer you.

Answer 3

acronym for light amplification by stimulated emission of radiation. Lasers are devices that amplify light and produce coherent light beams, ranging from infrared to ultraviolet.
According to the laser medium used, lasers are generally classified as solid state, gas, semiconductor, or liquid.

Answer 4

A laser does not just have to be red. What Javed is describing is a helium-neon laser. There are many other types of lasers that can emit a wide variety of other wavelengths (From radio to x-ray).

Answer 5

Laser=beam of light

Answer 6

A laser is a device that raises the energy state of a substance so that it emits light in an intense, narrow beam.

Answer 7

Light Amplification by Stimulation Emission of Radiation

Answer 8

It stands for Light Amplification by Stimulated Emission of Radiation. Basically, a really strong light :)