The internal resistance of an electric fan is 20 Ω. After connecting with the voltage of 220 V, the electric power consumed during normal operation is 66 W (1) What is the current passing through the electric fan motor during normal operation? (2) what is the power converted into mechanical energy and internal energy when the electric fan is working? What is the efficiency of the motor at this time? (3) if the electric fan blade is stuck and cannot rotate after the power is connected, how much is the current passing through the motor? How much is the electric power and heating power consumed by the motor?

The internal resistance of an electric fan is 20 Ω. After connecting with the voltage of 220 V, the electric power consumed during normal operation is 66 W (1) What is the current passing through the electric fan motor during normal operation? (2) what is the power converted into mechanical energy and internal energy when the electric fan is working? What is the efficiency of the motor at this time? (3) if the electric fan blade is stuck and cannot rotate after the power is connected, how much is the current passing through the motor? How much is the electric power and heating power consumed by the motor?

①66w/220v=0.3A
② Internal energy 0.3A * 20 Ω = 6W
Mechanical energy 66w-6w = 60W
Efficiency 60 / 66
③220V/20Ω=11A
Consumed electric power = heating power = 220V * 11A

If a motor is connected to both ends of a 220 V power supply with a current of 4A and a resistance of 4 Ω, there are many answers to why the heat is generated every minute,
One 3480, one 52800

A 3840 (not 3480) is correct
52800 is the total work, which is calculated by w = UI. If this formula is used to calculate heat, it can only be used in pure resistance circuit
The general formula of heat calculation is q = the square of I * t

The coil of a motor has a resistance of 5 ohm. When it works normally in the 220 V lighting circuit, the current is 4a
Find: (1) the power of the motor
(2) Heating power of the motor
(3) Please explain the difference between the above two groups of power from the perspective of energy

(1)220x4=880w
(2)4x4x5=80w
(3) Generating power is used to convert into energy you need, such as kinetic energy. Heating power is the energy consumed by internal resistance, which is used for heating

Is the supply voltage of parallel circuit equal to the voltage at both ends of each branch?
When doing the experiment, the parallel circuit uses 3V power supply, but the voltage at both ends of the measuring appliance is 2.4V. Why is it not equal to the power supply voltage?

The power supply also has internal resistance, and the 3V on the battery represents the electromotive force, which is the ability of the battery to convert other energy into electric energy. The branch voltage of the parallel circuit is equal to the power supply voltage. It is an ideal state only when the internal resistance of the power supply is 0. But in fact, the power supply has internal resistance, so the whole power supply can be regarded as a superconducting power supply (