1. What is Ohm’s Law?
Answer:
Ohm’s Law states that the current (I) flowing through a conductor between two points is directly proportional to the voltage (V) across the two points and inversely proportional to the resistance (R).
V=I×RV = I \times R Where:
- VV = Voltage (Volts)
- II = Current (Amperes)
- RR = Resistance (Ohms)
2. What is the difference between AC and DC?
Answer:
- AC (Alternating Current): The flow of electric charge periodically reverses direction. AC is used for power transmission and is commonly found in household outlets.
- DC (Direct Current): The flow of electric charge is in one direction only. Batteries provide DC power.
3. What is a capacitor and how does it work?
Answer:
A capacitor is a two-terminal electronic component that stores electrical energy in an electric field. It consists of two conductive plates separated by an insulating material (dielectric). When a voltage is applied, charge accumulates on the plates, creating an electric field. Capacitors are used for filtering, energy storage, and voltage regulation in electrical circuits.
4. What is the difference between a series and parallel circuit?
Answer:
- Series Circuit: Components are connected end-to-end, so the same current flows through all components. The total resistance is the sum of the individual resistances.
- Parallel Circuit: Components are connected across common points, providing multiple paths for current. The total resistance decreases, and the voltage across all components is the same.
5. What is the purpose of a transformer?
Answer:
A transformer is an electrical device used to change the voltage of an alternating current (AC). It can either step up (increase) or step down (decrease) voltage levels based on the turns ratio of the primary and secondary coils. Transformers are used in power transmission to reduce energy loss.
6. What is the difference between a fuse and a circuit breaker?
Answer:
- Fuse: A fuse is a safety device that protects a circuit by breaking the connection when the current exceeds a certain limit. It contains a wire that melts when too much current passes through, stopping the current flow.
- Circuit Breaker: A circuit breaker is an automatic electrical switch that protects the circuit by interrupting the flow of current when an overload or short circuit occurs. Unlike a fuse, it can be reset and reused.
7. What is power factor?
Answer:
Power factor is the ratio of real power (kW) to apparent power (kVA) in an electrical system. It indicates how efficiently the electrical power is being used.
Power Factor=Real Power (kW)Apparent Power (kVA)\text{Power Factor} = \frac{\text{Real Power (kW)}}{\text{Apparent Power (kVA)}} A power factor close to 1 means efficient power usage, while a lower power factor indicates inefficiencies due to reactive power.
8. What is an inductor?
Answer:
An inductor is a passive electrical component that stores energy in a magnetic field when current flows through it. Inductors oppose changes in current and are commonly used in filters, inductive heating, and energy storage applications.
9. What is the role of a rectifier in a power supply?
Answer:
A rectifier is a device used to convert alternating current (AC) into direct current (DC). It allows current to flow in only one direction, typically using diodes in various configurations (half-wave, full-wave) to rectify the AC signal.
10. What is the significance of the frequency of AC supply?
Answer:
The frequency of an AC supply refers to how many times the current alternates per second. It is measured in Hertz (Hz). In most countries, the standard frequency is 50 Hz or 60 Hz, depending on the region. The frequency affects the performance of electrical appliances and machines, especially those with motors.
11. What is a diode?
Answer:
A diode is a semiconductor device that allows current to flow in only one direction, acting as a one-way valve. It is used in rectifiers, voltage regulation, and signal processing.
12. What is a motor and how does it work?
Answer:
An electric motor is a device that converts electrical energy into mechanical energy. It operates on the principle of electromagnetic induction: a current-carrying conductor (usually a coil) placed in a magnetic field experiences a force that causes it to move, producing mechanical work. There are DC motors and AC motors, depending on the type of current they use.
13. What is Kirchhoff’s Current Law (KCL)?
Answer:
Kirchhoff’s Current Law states that the total current entering a junction (or node) is equal to the total current leaving the junction. In other words, the sum of currents at any point in a circuit is zero: ∑Iin=∑Iout\sum I_{in} = \sum I_{out}
14. What is Kirchhoff’s Voltage Law (KVL)?
Answer:
Kirchhoff’s Voltage Law states that the sum of the electrical potential differences (voltage) around any closed loop or circuit is zero. This is because a circuit loop is a closed conducting path, and the total voltage supplied by sources is equal to the total voltage drop across components: ∑V=0\sum V = 0
15. What is the role of a ground in electrical circuits?
Answer:
Grounding provides a safe path for excess current (such as from a fault or surge) to flow into the earth, preventing electrical shocks and protecting electrical equipment. It ensures the safety of both people and systems by maintaining a reference point for voltages.