# Objective Questions on Inductor | Page – 4

1. The unit of inductive susceptance is

The unit of inductive susceptance is Siemens. Susceptance (symbolized with B) is the opposite of reactance. Inductive susceptance becomes exactly like the formula for capacitive reactance, except that it of course uses inductorrather than capacitance.

2. An inductor supplied with 100 V with a frequency of 10 kHz and passes a current of 15.92 mA. The value of inductor is

Here the supply voltage is 100 V and current through the inductor is 15.92 mA
∴ Impedance of the inductor is

Expression for value of inductive impedance is given by ZL = 2πfL
Here, frequency f = 10 KHz, hence,

Now, comparing, equation (1) and (2) we get,

3. Which of the following case represents the largest mmf ?

The mmf of any magnetic circuit is measured as a product of number of turns in the coil and current passing through that coil. Hence if I current flows through N number of turns in a coil the mmf will be NI.

4. A 100 mH inductor is connected across a supply for 50 V AC. For which of the following frequency the circuit will have least rms current?

The impedance of a inductor is directly proportional to its supply frequency. RMS value of the current through the inductor is supply voltage/impedance. So, it can be concluded that current in inductor is inversely proportional to its supply frequency.

5. A 200 mH inductor is connected across a supply for 100 V AC. For which of the following frequency the circuit will have highest rms current?

The impedance of a inductor is directly proportional to its supply frequency. RMS value of the current through the inductor is supply voltage/impedance. So, it can be concluded that current in inductor is inversely proportional to its supply frequency.

6. The energy stored in an inductor of inductor L Henry is represented as,

The voltage in an inductor is given as,

7. The instantaneous power in an inductor is proportional to the

8. The voltage induced in an inductor of L Henry is represented as,

9. Statement 1 :- Inductor doesn’t accept sudden changes in current.
Statement 2 :- Inductor doesn’t accepts sudden changes in voltage.

In order to accept sudden changes in current, it requires infinite energy, infinite power and infinite voltage, those are not desirable. So inductor doesn’t accept sudden changes in current.

10. Which energy is stored in inductor and capacitor?

The property of inductor is which stores magnetic field energy and electric field energy stored by capacitor.

11. The strength of current in 1 Henry inductor changes at a rate of 2 A / sec. Find the voltage across it and determine the magnetic of energy stored in the inductor after 2 secs?

12. The switch is closed at time t = 0, then the voltage across the inductor is given by

At the time t = 0+, inductor will acts as open circuit. Hence voltage across the inductor is V0.

13. Two inductances are in series their equivalent will be

The equivalent induactance when two inductances are connected in series, is equal to their sum which is always like resistances.

14. Property of pure inductor is

Pure inductor only stores energy but does not dissipate it.

15. The max value of mutual inductor of two inductively coupled coils with self inductor L1 = 49 mH & L2 = 81 mH

16. A coil has an inductive reactance of 4 ohm and a resistance of 3 ohm the admittance of the coil is