Question

A motor, a lamp and a 12 V battery are connected in series. The resistance of the motor is 10 Ω and the resistance of the lamp is 20 Ω. The current through the lamp is 0.4 A.
a) Determine the current through the motor.
b) Calculate the total resistance of the circuit.
c) If the potential difference across the motor is 4 V, what is the potential difference across the lamp?

Answer 1

Answer:

R1 = 10 Ohms.

R2 = 20 Ohms.

I1 = 1.2A.

1. I1 + I2 = 1.8A.

1.2 + I2 = 1.8, I2 = 0.6A.

2. V = I1*R1 = 1.2 * 10 = 12 Volts.

3. Rt = R1*R2/(R1+R2) = 10*20/(10+20) = 6.67 Ohms.