Voltage drops in a series circuit

[rachelmaddiee]

Homework Statement

Three 15.0-W resistors are connected in parallel across a 30.0-V battery. Please show all work. (ref: p.624-634)
a) Find the current through each branch of the circuit. b) Find the equivalent resistance of the circuit.
c) Find the current through the battery.

Relevant Equations

I = Vsource/R and R = RA + RB

Known: V source = 30.0 V
, R1 = 15.0 W, R2 = 15.0 W, R3 = 15.0 W

To determine the current, first find the equivalent resistance.
I = Vsource/R and R = RA + RB
= Vsource/RA + RB
30.0 V/15.0 W + 15.0 W + 15.0 W
= 1.5 A

This is as far as I could do the work for this question. I’m having trouble..

 

[Delta2]

The resistors are connected in parallel, hence the equation R=RA+RB does not apply because it is for resistors in series. The total resistance for three resistors in parallel is given by the equation $$\frac{1}{R_{TOT}}=\frac{1}{R_1}+\frac{1}{R_2}+\frac{1}{R_3}$$.
a) asks for the current through each branch of the circuit, you don't need to calculate the total resistance to answer this.

 

[phinds]

Problem statement makes no sense. It doesn't matter what the wattage of a resistor is (except to the extent that you don't want to burn it out), it matters what the resistance is and this problem statement doesn't give that.

If you are somehow confused about terminology and think that "W" means ohms (it doesn't, "R" does) then your problem is this:

30.0 V/15.0 W + 15.0 W + 15.0 W
= 1.5 A

 

[Delta2]

Yes i think by "W" he/she actually means "Ohm" .