Question

A typical incandescent bulb has an efficiency of about 10%. What current is needed for a bulb with a resistance of 1.5×102Ω to output power of 6.0 W?

Answer 1

Solution;

$P=I^2R$

$6=I^2×1.5×10^2$

$I^2=0.4$

$I=0.6324A$