Inductors: principles and applications MCQs

Q1: The primary property of an inductor is to:
(A) Store energy in an electric field
(B) Store energy in a magnetic field
(C) Resist the flow of current
(D) Amplify voltage
Answer: (B) Store energy in a magnetic field

Q2: The SI unit of inductance is:
(A) Tesla
(B) Henry
(C) Weber
(D) Farad
Answer: (B) Henry

Q3: Inductors oppose changes in:
(A) Voltage
(B) Current
(C) Power
(D) Resistance
Answer: (B) Current

Q4: The inductance of a coil depends on:
(A) Number of turns of the coil
(B) Core material
(C) Cross-sectional area of the coil
(D) All of the above
Answer: (D) All of the above

Q5: What is the self-inductance of a coil?
(A) The property of a coil to store energy in the form of an electric field
(B) The property of a coil to oppose changes in its own current
(C) The property of a coil to conduct current
(D) The resistance of the coil
Answer: (B) The property of a coil to oppose changes in its own current

Q6: In an ideal inductor, the phase difference between voltage and current is:
(A) 0°
(B) 45°
(C) 90°
(D) 180°
Answer: (C) 90°

Q7: In an inductor, the induced voltage is proportional to:
(A) The resistance of the coil
(B) The rate of change of current
(C) The applied current
(D) The capacitance of the circuit
Answer: (B) The rate of change of current

Q8: The energy stored in an inductor is given by:
(A) $W = \frac{1}{2} L I^2$
(B) $W = L \times I$
(C) $W = \frac{1}{2} L V^2$
(D) $W = \frac{1}{2} C V^2$
Answer: (A) $W = \frac{1}{2} L I^2$

Q9: Inductors are commonly used in:
(A) High-pass filters
(B) Low-pass filters
(C) Band-pass filters
(D) All of the above
Answer: (D) All of the above

Q10: The primary function of an inductor in a transformer is to:
(A) Increase current
(B) Store energy temporarily
(C) Couple energy between two circuits
(D) Convert DC to AC
Answer: (C) Couple energy between two circuits

Q11: In a DC circuit, the inductor behaves like:
(A) A short circuit
(B) An open circuit
(C) A resistor
(D) A capacitor
Answer: (A) A short circuit

Q12: Inductors are used in electric motors to:
(A) Increase speed
(B) Reduce power loss
(C) Generate a magnetic field
(D) Decrease current
Answer: (C) Generate a magnetic field

Q13: Which of the following applications uses inductors?
(A) Radio tuning circuits
(B) Power supply filters
(C) Energy storage in DC-DC converters
(D) All of the above
Answer: (D) All of the above

Q14: Inductors in series result in:
(A) Increased total inductance
(B) Decreased total inductance
(C) The same inductance as a single inductor
(D) Zero inductance
Answer: (A) Increased total inductance

Q15: In AC circuits, inductors are used to:
(A) Block AC signals
(B) Impede changes in AC current
(C) Rectify current
(D) Amplify current
Answer: (B) Impede changes in AC current