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Most Important Selected Qs for JEE AdvancedPhysicsDual Nature of Matter

A beam of light has two wavelengths 3100 Å and 4133 Å with a total intensity of 12.8 ~W / m ^2 equally distributed between the two wavelengths. The beam falls normally on an area of a clean metallic surface of work function 3.1 eV . Assume that there is no loss of energy by reflection and that each energetically capable photon ejects one electron. How many electrons will emit per second from the face area?

Options

  1. A2 10¹⁹
  2. B10¹⁹
  3. C10¹⁸
  4. D2 10¹⁸

Correct answer

B. 10¹⁹

Step-by-step solution

_ = hc = 12400 3.1 =4000 Å so only 3100 Å will emit electrons. Then I 2 = n ( hc ) n = 12.8 2 ( hc )=10¹⁹

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