One of the formulas for electrical power is
Power = (current²) x (resistance) .
This is a very handy formula to use right now. because this question TELLS us the current and the resistance, and it wants us to find the power. Let's go:
Power = (current²) x (resistance) .
= (28.5 A)² x (12.8 ohms)
= 10,396.8 watts .
Choice-D is apparently the one to pick.
This is a serious lamp ... one you don't want to mess with.
A typical incandescent lamp is maybe 20% efficient ...
20% of the power it uses gets turned into light, and the
other 80% gets turned into heat. If that's true of the lamp
in this question, then when it's turned on ...
-- it shines with about 2,080 watts of light;
-- it oozes about 8,320 watts of heat into the room ... about
the same as five or six toasters, or seven blow-dryers, all
running full-blast.
