Question

The luminous flux of a $60$ $W$ power bulb is $600$ lumen. The luminous efficiency of the bulb will be :

• A. $60$ lm $W^{-1}$
• B. $600$ lm $W^{-1}$
• C. $0.1$ lm $W^1$
• D. $10$ lm $W^{-1}$

Answer 1

The correct option is D $10$ lm $W^{-1}$

Luminous efficiency,
$\eta =\frac{luminousflux}{Power}=\frac{600lumen}{60W}=10lm{W}^{-1}$