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JEE MainPhysicsDual Nature of Matter

Two lasers A and B emit monochromatic light. The ratio of the power of laser A to that of laser B is 3:1 . If the ratio of the number of photons emitted per second by laser A to that by laser B is 2:1 , the ratio of their wavelengths _A : _B is :

Options

  1. A3:2
  2. B2:3
  3. C6:1
  4. D1:6

Correct answer

B. 2:3

Step-by-step solution

The power of a source is given by P = n hc , where n is the number of photons emitted per second. Rearranging for wavelength, we get = nhc P . Taking the ratio for lasers A and B: _A _B = ( n_A n_B ) ( P_B P_A ) Given that P_A P_B = 3 1 and n_A n_B = 2 1 , we substitute these values: _A _B = ( 2 1 ) ( 1 3 ) = 2 3 Thus, the ratio of their wavelengths is 2:3 . Answer: 2:3

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