Question

A series circuit contains two devices, one with a resistance of 10 ohms and one with a resistance of 4 ohms. If the generator supplies a voltage of 42 V, what is the magnitude of the current? A. 2 A B. 3 A C. 1.75 A D. 1.33 A

Answer 1

First you calculate the total resistance. Since the resistors are connected in series, the total equivalent resistance is:
Rtotal = R1 + R2 = 10 + 4 = 14 ohms

Now you calculate the electrical current with Ohm's law:
I = U/Rtotal = 42/14 = 3A

Correct answer: B. 3 A