Physics-
General
Easy

Question

The maximum velocity of electrons emitted from a metal surface is V. When frequency of light falling on it is f. The maximum velocity when frequency becomes 4f is

  1. 2 V    
  2. > 2 V    
  3. < 2 V    
  4. Between 2 V and 4 V    

The correct answer is: > 2 V


    because E equals W subscript 0 end subscript plus fraction numerator 1 over denominator 2 end fraction m v subscript m a x end subscript superscript 2 end superscript Þ v square root of fraction numerator 2 left parenthesis h f minus W subscript 0 end subscript right parenthesis over denominator m end fraction end root subscript m a x end subscript
    If frequency becomes 4f then
    V ´ equals square root of fraction numerator 2 left parenthesis h cross times 4 f minus W subscript 0 end subscript right parenthesis over denominator m end fraction end root equals 2 square root of fraction numerator 2 open parentheses h f minus fraction numerator W subscript 0 end subscript over denominator 4 end fraction close parentheses over denominator m end fraction end rootÞ V ´ greater than 2 V

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