If I have an electric circuit with two consumers P1= 80 W and P2=40W, the are parallel and the voltage U=120 V, what is the resistance of both consumers?How large is the net resistance of the circuit? What can you tell about the streams passing the consumers?

Question

anonymous · Answer

Since the circuits are in parallel, they will have the same voltage across them. 

Electrical power is expressed as$$P = {V^2  \over R}$$ You can solve for R for each circuit. 

The net resistance found from the equivalent resistance equation for parallel resistors: $${1 \over R_{eq}} = { 1 \over R_1 } + {1 \over R_2} $$