COIL EXAM QUESTIONS WITH VERIFIED ANSWERS 2
VERSIONS
Comprehensive Exam Bank: Multiple Choice Questions
1. The emf produced in a coil is directly proportional to the rate of change of
current with time. What is the proportionality constant called?
A) Resistance
B) Capacitance
C) Inductance
D) Conductance
Correct Answer: C) Inductance
Rationale: If a current that varies with time flows through a coil, an emf is induced. The
emf produced is directly proportional to the rate of change of current with time. The
proportionality constant is called Inductance .
2. What is the formula for induced emf in a coil in terms of inductance?
A) E = L × ΔI/Δt
B) E = R × I
C) E = C × ΔV/Δt
D) E = P × I
Correct Answer: A) E = L × ΔI/Δt
Rationale: The induced emf equals the inductance times the rate of change of current. This
is the fundamental relationship defining inductance .
3. Which of the following circuit elements opposes changes in circuit current?
A) Capacitance
,B) Inductance
C) Resistance
D) All of the above
Correct Answer: B) Inductance
Rationale: Inductance specifically opposes changes in circuit current. This is a defining
property of inductors .
4. An inductor works by storing energy in what form?
A) Electric field
B) Magnetic field
C) Thermal energy
D) Chemical energy
Correct Answer: B) Magnetic field
Rationale: An inductor works by storing energy as a magnetic field when current flows
through it .
5. The phenomenon by which there is an induced current in one coil due to current
in a neighbouring coil is called:
A) Self-inductance
B) Mutual inductance
C) Electromagnetism
D) Susceptance
Correct Answer: B) Mutual inductance
Rationale: Mutual inductance is the phenomenon by which there is an induced current in
one coil due to current in a neighbouring coil .
6. What happens to the inductance if the iron core is removed from an iron-cored
coil?
A) It increases
,B) It decreases
C) It remains the same
D) It becomes zero
Correct Answer: B) It decreases
Rationale: Removing the iron core reduces the coil's inductance because air has lower
permeability than iron .
7. Higher self-inductance of a coil results in:
A) Lesser weber-turns
B) Lower induced emf
C) Greater flux produced
D) Longer delay in establishing a steady current
Correct Answer: D) Longer delay in establishing a steady current
Rationale: Higher self-inductance creates a greater opposition to changes in current,
resulting in a longer delay before the current reaches a steady state .
8. The inductance of a coil is NOT affected by which of the following?
A) The length of the coil
B) Number of turns
C) The material of the core
D) The diameter of the wire
Correct Answer: D) The diameter of the wire
Rationale: Inductance is affected by the length of the coil, number of turns, and core
material, but NOT by the diameter of the wire .
9. In a small inductance, energy is:
A) Stored and released slowly
B) Stored and released quickly
, C) Not stored at all
D) Converted to heat
Correct Answer: B) Stored and released quickly
Rationale: In a small inductance, energy is stored and released quickly due to the lower
time constant .
10. Which of the following is a type of ignition coil system used in modern
vehicles?
A) Distributorless Ignition System (DIS)
B) Coil-On-Plug (COP)
C) Traditional single coil
D) All of the above
Correct Answer: D) All of the above
Rationale: Vehicles use different types of ignition coils including Coil-On-Plug (COP),
Distributorless Ignition System (DIS) coil packs, and traditional single coil systems .
11. In a Coil-On-Plug (COP) ignition system, where is the coil located?
A) On the firewall
B) On the fender
C) Directly on top of the spark plug
D) In the distributor
Correct Answer: C) Directly on top of the spark plug
Rationale: COP coils sit right on top of the spark plug and are usually bolted to the valve
cover or cam cover .
12. What is a common symptom of a failing ignition coil?
A) Engine misfires
B) Improved fuel economy
VERSIONS
Comprehensive Exam Bank: Multiple Choice Questions
1. The emf produced in a coil is directly proportional to the rate of change of
current with time. What is the proportionality constant called?
A) Resistance
B) Capacitance
C) Inductance
D) Conductance
Correct Answer: C) Inductance
Rationale: If a current that varies with time flows through a coil, an emf is induced. The
emf produced is directly proportional to the rate of change of current with time. The
proportionality constant is called Inductance .
2. What is the formula for induced emf in a coil in terms of inductance?
A) E = L × ΔI/Δt
B) E = R × I
C) E = C × ΔV/Δt
D) E = P × I
Correct Answer: A) E = L × ΔI/Δt
Rationale: The induced emf equals the inductance times the rate of change of current. This
is the fundamental relationship defining inductance .
3. Which of the following circuit elements opposes changes in circuit current?
A) Capacitance
,B) Inductance
C) Resistance
D) All of the above
Correct Answer: B) Inductance
Rationale: Inductance specifically opposes changes in circuit current. This is a defining
property of inductors .
4. An inductor works by storing energy in what form?
A) Electric field
B) Magnetic field
C) Thermal energy
D) Chemical energy
Correct Answer: B) Magnetic field
Rationale: An inductor works by storing energy as a magnetic field when current flows
through it .
5. The phenomenon by which there is an induced current in one coil due to current
in a neighbouring coil is called:
A) Self-inductance
B) Mutual inductance
C) Electromagnetism
D) Susceptance
Correct Answer: B) Mutual inductance
Rationale: Mutual inductance is the phenomenon by which there is an induced current in
one coil due to current in a neighbouring coil .
6. What happens to the inductance if the iron core is removed from an iron-cored
coil?
A) It increases
,B) It decreases
C) It remains the same
D) It becomes zero
Correct Answer: B) It decreases
Rationale: Removing the iron core reduces the coil's inductance because air has lower
permeability than iron .
7. Higher self-inductance of a coil results in:
A) Lesser weber-turns
B) Lower induced emf
C) Greater flux produced
D) Longer delay in establishing a steady current
Correct Answer: D) Longer delay in establishing a steady current
Rationale: Higher self-inductance creates a greater opposition to changes in current,
resulting in a longer delay before the current reaches a steady state .
8. The inductance of a coil is NOT affected by which of the following?
A) The length of the coil
B) Number of turns
C) The material of the core
D) The diameter of the wire
Correct Answer: D) The diameter of the wire
Rationale: Inductance is affected by the length of the coil, number of turns, and core
material, but NOT by the diameter of the wire .
9. In a small inductance, energy is:
A) Stored and released slowly
B) Stored and released quickly
, C) Not stored at all
D) Converted to heat
Correct Answer: B) Stored and released quickly
Rationale: In a small inductance, energy is stored and released quickly due to the lower
time constant .
10. Which of the following is a type of ignition coil system used in modern
vehicles?
A) Distributorless Ignition System (DIS)
B) Coil-On-Plug (COP)
C) Traditional single coil
D) All of the above
Correct Answer: D) All of the above
Rationale: Vehicles use different types of ignition coils including Coil-On-Plug (COP),
Distributorless Ignition System (DIS) coil packs, and traditional single coil systems .
11. In a Coil-On-Plug (COP) ignition system, where is the coil located?
A) On the firewall
B) On the fender
C) Directly on top of the spark plug
D) In the distributor
Correct Answer: C) Directly on top of the spark plug
Rationale: COP coils sit right on top of the spark plug and are usually bolted to the valve
cover or cam cover .
12. What is a common symptom of a failing ignition coil?
A) Engine misfires
B) Improved fuel economy
