Laser

This situation shows that

• light travels in a straight line

• light is everywhere

• light penetrates certain objects

• light is produces by the Sun

Acronym for LASER is

• Light Absorption by Stimulated Emission of Radiation

• Light Amplification by Stimulated Emission of Radiation

• Light Alteration by Stimulated Emission of Radiation

• Light Attenuation by Stimulated Emission of Radiation

Which of the following statements are true?

1. LASER is used as optical source in single mode fibers.
2. LASER lights are highly incoherent.

• 1. is true and 2. is false

• 1. is false and 2. is true

• Both 1 & 2 are true

• Both 1 & 2 are false

Naturally occuring process in a LASER is

• Stimulated Emission

• Absorption

• Spontaneous Emission

• Population Inversion

The process in which the electrons in the ground state are vibrated to the excited states by providing extra energy from energy sources is called as

• Population Inversion

• Spontaneous emission

• Stimulated emission

• Pumping

Light amplification in LASER is achieved by

• Population inversion

• Stimulated emission

• Spontaneous emission

• Pumping

Minimum number of energy states required to achieve population inversion is

• 1

• 2

• 3

• 4

The lifetime of electrons are more in

• Pump state

• Excited state

• Meta stable state

• Ground state

Laser is a coherent source of light. This means all the light waves....

• are out of phase

• are in phase

• have different directions

• have same direction

Laser is a monochromatic source of light. This means all the light waves have...

• same wavelength

• same phase

• same intensity

• same direction