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Five lumen/watt is the luminous efficiency of a lamp and its luminous intensity is 35 candela. The power of the lamp is

Physics-General

  1. 36 W    
  2. 88 W    
  3. 80 W    
  4. 176 W    

    Answer:The correct answer is: 88 WEfficiency of light source
    eta equals fraction numerator phi over denominator p end fraction..... (i)
    and L equals fraction numerator phi over denominator 4 pi end fraction..... (ii)
    From equation (i) and (ii)
    rightwards double arrow p equals fraction numerator 4 pi L over denominator eta end fraction equals fraction numerator 4 pi cross times 35 over denominator 5 end fraction almost equal to 88 W.

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