Question

56. Which of the following is a unique property of laser?
(A) Directional
(B) Speed
(C) Coherence
(D) Wavelength​

Answer 1

coherence

Explanation:

Coherence is an important characteristic of laser beam because in laser beams, the wave trains of the same frequency are in phase/ Due to high coherence it results in extremely high power.

Answer 2

Answer:

The correct option is (C) Coherence.

Explanation:

• If two waves have same the frequency, same the wavelength and a constant phase difference. then these waves are known as coherent waves.
• The source from which the coherent waves come is called coherent source.
• This phenomenon is known as coherence.
• There are two types of coherence.

1. Spatial coherence
2. Temporal coherence.

• Lasers are frequently used as coherent source.
• Laser beams are monochromatic, and their wavelengths are in phase in space and time.

Conclusion:

Coherence is the unique property of a laser.