1. What is Ohm’s Law?
Ohm’s Law states that the current flowing through a conductor is directly proportional to the voltage across it and inversely proportional to the resistance of the conductor.

2. What is the difference between AC and DC?
AC (Alternating Current) continuously changes its magnitude and direction, while DC (Direct Current) maintains a constant magnitude and flows in one direction.

3. Define voltage.
Voltage is the electric potential difference between two points, which determines the amount of current flowing between them.

4. What is an electric circuit?
An electric circuit is a closed path or loop through which electric current can flow.

5. Explain the concept of resistance.
Resistance is the opposition to the flow of electric current in a circuit. It is measured in ohms (Ω).

6. What is the difference between series and parallel circuits?
A series circuit has only one path for the current to flow, while a parallel circuit has multiple paths for the current to divide and flow.

7. What is the purpose of a fuse in an electrical circuit?
A fuse acts as a protective device that interrupts the flow of current in case of excessive current or a short circuit to prevent damage to the circuit.

8. What is the role of a circuit breaker?
A circuit breaker is an electrical switch that automatically interrupts the flow of current in a circuit when it detects an overload or a short circuit.

9. Define electric power.
Electric power is the rate at which electrical energy is converted into other forms of energy. It is measured in watts (W).

10. Explain the concept of an electric motor.
An electric motor is a device that converts electrical energy into mechanical energy. It uses the magnetic force produced by the flowing current to generate motion.

11. What is the difference between insulation and isolation?
Insulation refers to the process of covering a conductor with a non-conducting material to prevent the flow of current, while isolation refers to the complete physical separation of an electrical circuit from its surroundings.

12. What is the purpose of a transformer?
A transformer is used to change the voltage level of an AC electrical circuit. It either steps up the voltage (step-up transformer) or steps it down (step-down transformer).

13. Define inductance.
Inductance is the property of an electrical conductor or coil that opposes a change in the flow of current. It is measured in henries (H).

14. What is capacitance?
Capacitance is the ability of a system to store an electric charge. It is measured in farads (F).

15. Explain the concept of grounding.
Grounding refers to the process of connecting an electrical circuit or device to the Earth to prevent the buildup of static electricity and to provide a safe path for current in case of a fault.

16. What is the function of a diode?
A diode is an electronic component that allows current to flow in one direction while blocking it in the opposite direction. It is used for rectification, voltage regulation, and signal processing.

17. What is the difference between analog and digital signals?
Analog signals are continuous and represent a range of values, while digital signals are discrete and represent only two states – ON or OFF.

18. Define the terms ‘watt’, ‘volt’, and ‘ampere’.
– Watt: A unit of power, equal to one joule of energy per second.
– Volt: A unit of voltage or electric potential difference.
– Ampere: A unit of electric current.

19. What is the purpose of a relay in an electrical circuit?
A relay is an electromagnetic switch that is used to control the flow of current in a circuit. It allows a small control signal to switch on or off a larger electrical circuit.

20. Explain the concept of inrush current.
Inrush current is the initial surge of current that flows into an electrical device or component when it is first turned on. It can be several times higher than the steady-state current and needs to be considered when selecting protective devices for the circuit.

1. What is the difference between a rectifier and an inverter?
A rectifier converts AC (Alternating Current) to DC (Direct Current), while an inverter converts DC to AC.

2. Define impedance in an electric circuit.
Impedance is the total opposition to the flow of alternating current in an electric circuit. It includes both resistance and reactance.

3. How is the power factor of an electrical circuit calculated?
The power factor of an electrical circuit is calculated by dividing the real power (Watts) by the apparent power (Volt-Amperes).

4. What is the purpose of a transformer in an electrical system?
A transformer is used to change the voltage level of electric power transmission from one level to another, for efficient distribution.

5. Explain what is harmonics in an electrical system.
Harmonics are electric voltages or currents that are integer multiples of the fundamental frequency. They can cause distortion and overload in electrical systems.

6. What are the advantages of three-phase power over single-phase power?
Three-phase power provides improved power transfer efficiency and smoother operation for electric motors compared to single-phase power.

7. What is the purpose of a diode in an electrical circuit?
A diode is used to allow current flow in only one direction, blocking it in the opposite direction. It is commonly used in rectifiers.

8. Differentiate between insulation resistance and electrical resistance.
Insulation resistance measures the resistance offered by the insulating material to the flow of current, while electrical resistance measures the opposition to current flow in a conducting material.

9. What is the role of a capacitor in an electric circuit?
A capacitor stores electrical energy and releases it when needed, providing reactive power to the circuit and smoothing voltage fluctuations.

10. Explain what is a surge arrester and its function.
A surge arrester is a protective device used to limit high voltages and divert surge currents caused by lightning or other transients to the ground, thus protecting electrical equipment.

11. How is short-circuit current calculated in a power system?
Short-circuit current is calculated by dividing the rated voltage of the system by the total impedance of the system at the fault location.

12. What is the purpose of a ground fault circuit interrupter (GFCI)?
A GFCI is designed to protect against electric shocks caused by ground faults. It detects imbalanced currents and quickly interrupts the circuit to prevent electrical accidents.

13. Explain the concept of electrical power factor correction.
Power factor correction involves using capacitors to offset the reactive power in an electrical system, leading to improved power factor, efficiency, and reduced voltage drops.

14. What is the difference between insulation and dielectric strength?
Insulation strength refers to the ability of an insulating material to resist breakdown when subjected to voltage, while dielectric strength refers to the maximum voltage an insulating material can withstand without breakdown.

15. How does a ground-fault relay work?
A ground-fault relay monitors the current flowing in the neutral (grounded) conductor. If an imbalance is detected, indicating a ground fault, it trips the circuit breaker or isolates the fault.

16. What is the purpose of a circuit breaker in an electrical system?
A circuit breaker is a protective device that automatically interrupts the electrical circuit in the event of overload, short circuit, or ground fault, preventing damage to equipment and electrical fires.

17. Explain the principle of a variable frequency drive (VFD).
A VFD adjusts the frequency and voltage of the power supplied to an electric motor, allowing control over its speed and torque. It enables energy-efficient operation and precise motor control.

18. Define the capacitance of a capacitor.
The capacitance of a capacitor is the ability of the capacitor to store an electric charge, measured in farads (F).

19. What is the concept of electrical grounding?
Electrical grounding involves connecting electrical systems or equipment to the Earth’s conductive surface to prevent electric shocks, limit voltage fluctuations, and ensure safety.

20. How does a synchronous motor differ from an induction motor?
A synchronous motor rotates at a speed directly proportional to the frequency of the applied voltage, while an induction motor’s speed is slightly lower than the synchronous speed due to slip. Synchronous motors are used in applications requiring precise speed control.