Question

1) An electric heater consumes electrical energy at a rate of

P = 150 W

when connected to a battery with an emf of 120 V.

(a) What is the current in the heater?
A

(b) If you wish to increase the power consumption to 300 W, by what factor should the heater resistance be changed?

Rfinal

Rinitial

=  

(c) What is the maximum power that could be drawn if the circuit contained a circuit breaker that limited the current to no more than 25 A?
W

Answer 1

Solution: Given that p-150 w We know that P IV P 150 V 120 T-1.25A We know that V2 1202 P150 If power increased to 300W 1202 P 300 Change in resistance AR 96-48482 Resistance changes to half of its initial value P=VI = 1 20 x 25 P 3000 W