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Question
In a laser tube, all the photons
Options
have same wavelength
have same energy
move in same direction
move with same speed
Solution
move with same speed
All the photons emitted in the laser move with the speed equal to the speed of light (c = 3×108 m/s).
Ideally, the light wave through the laser must be coherent, but in practical laser tubes, there is some deviation from the ideal result. Thus, the photons emitted by the laser have little variations in their wavelengths and energies as well as the directions, but the velocity of all the photons remains same.
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