Question

Which one of the following statements is incorrect about laser?
A) It is a technique for producing intense beams of light, ultraviolet or infrared radiation of different wavelength.
B) Even in diamond laser beam can drill a hole.
C) A variety of lasers have been made from solids like the ruby crystal and semi conducting materials, liquids and gases.
D) All waves in laser travel in phase.

Answer 1

Question:

One option in the question is incomplete.

Question with correct option would be-

Which one of the following statements is incorrect about laser?

A) It is a technique for producing intense beams of light, ultraviolet or infrared radiation of different wavelength.

B) Even in diamond laser beam can drill a hole.

C) A variety of lasers have been made from solids like the ruby crystal and semi conducting materials, liquids and gases.

D) All waves in laser travel in different phase.

Answer:

D) All waves in laser travel in different phase. It is the right answer.

Explanation:

A laser produces a very narrow beam of light. It is very useful in many technologies and instruments. The light waves of laser travel together with their peaks all lined up and the laser beams are typically very narrow for this reason, also very bright, and can be focused into a very tiny spot.

All waves in a laser must be in the same phase to increase their intensity so, all the waves must be in same phase. If they were not in a phase the net intensity will not be maximum.

Thus, the incorrect statement is option (D) All waves in laser travel in different phase.

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