Optics Question 476

Question: If luminous efficiency of a lamp is 2 lumen/watt and its luminous intensity is 42 candela, then power of the lamp is

[AFMC 1998]

Options:

A) 62 W

B) 76 W

C) 138 W

D) 264 W

Show Answer

Answer:

Correct Answer: D

Solution:

Luminous flux =4π L

=4×3.14×42 = 528

Lumen Power of lamp =Luminous fluxLuminousefficiency

=5282=264 W



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