A vacuum cleaner is plugged into a 120.0-V socket and uses 2.4 A of current in normal operation when the back emf generated by the electric motor is 98.6 V. Find the coil resistance of the motor.

The resistance of the motor is 8.91 ohms.

Explanation:

Given that,

Voltage of the socket, V = 120 V

Current, I = 2.4 A

Back emf generated by the electric motor is, E = 98.6 V

We need to find the coil resistance of the motor. The new emf on the vacuum cleaner is

The resistance of the motor is given by :

So, the resistance of the motor is 8.91 ohms. Hence, this is the required solution.