What does Kirchhoff’s Voltage Law (KVL) state?
A The total current entering a junction equals the current leaving it.
B The total voltage around a closed loop is zero.
C Voltage is directly proportional to current.
D Current remains constant in a circuit.
KVL states that the sum of all voltage drops and rises in a closed loop equals zero, ensuring energy conservation.
Which material is commonly used as a dielectric in capacitors?
A Copper
B Paper
C Aluminum
D Silicon
Paper, mica, ceramic, and plastic are common dielectric materials used in capacitors to increase their storage capacity.
What does the term “electromotive force (EMF)” refer to?
A The force between two charges
B The energy supplied by a source per unit charge
C The resistance of a circuit
D The current in a circuit
EMF is the voltage generated by a source like a battery or generator, measured in volts.
Which device protects a circuit from excessive current?
A Inductor
B Capacitor
C Fuse
D Diode
A fuse melts when excessive current flows through it, breaking the circuit and protecting the components.
Which law governs the relationship between force, current, and magnetic field in an electric motor?
A Faraday’s Law
B Lenz’s Law
C Fleming’s Left-Hand Rule
D Kirchhoff’s Law
Fleming’s Left-Hand Rule determines the direction of force acting on a current-carrying conductor in a magnetic field.
What is the purpose of a transformer in an electrical system?
A To generate electricity
B To step up or step down voltage
C To convert AC to DC
D To store energy
Transformers use electromagnetic induction to modify voltage levels for efficient power transmission.
What does the term “impedance” refer to in an AC circuit?
A Opposition to direct current
B Opposition to alternating current
C Voltage drop across a resistor
D Capacitance in the circuit
Impedance is the total opposition to the flow of AC and includes resistance and reactance.
What happens to the total resistance in a parallel circuit when more resistors are added?
A Increases
B Decreases
C Remains the same
D Doubles
Adding resistors in parallel provides additional current paths, reducing the overall resistance of the circuit.
Which component allows current to flow only in one direction?
A Resistor
B Capacitor
C Diode
D Inductor
Diodes allow current to flow in one direction while blocking it in the reverse direction, acting as a one-way valve.
What is the primary purpose of grounding in electrical systems?
A To increase voltage
B To prevent overloading
C To provide a safe path for fault currents
D To regulate power
Grounding prevents electric shock by providing a safe path for excess currents to flow into the earth.
What is the frequency of standard AC supply in India?
A 50 Hz
B 60 Hz
C 100 Hz
D 120 Hz
The standard frequency for AC supply in India is 50 Hz.
Which component stores energy in the form of an electric field?
A Resistor
B Capacitor
C Inductor
D Transformer
Capacitors store electrical energy in the form of an electric field between their plates.
What is the SI unit of electric field strength?
A Weber
B Volt per meter
C Coulomb
D Ampere
Electric field strength is measured in volts per meter (\( \text{V/m} \)).
What is the function of a voltmeter?
A Measure current
B Measure voltage
C Measure resistance
D Measure power
Voltmeters measure the potential difference across a component and are connected in parallel.
What does a current transformer (CT) do?
A Steps up voltage
B Steps down current
C Converts AC to DC
D Stores energy
Current transformers reduce high currents to lower values for safe measurement and monitoring.
Which component is used to oppose sudden changes in current?
A Capacitor
B Resistor
C Inductor
D Diode
Inductors resist changes in current by inducing a back EMF, stabilizing the circuit.
What is the primary function of a resistor in an electrical circuit?
A Increase voltage
B Limit current
C Store charge
D Amplify signals
Resistors control and limit current to protect other components in the circuit.
What happens when a conductor is moved through a magnetic field?
A A force is generated
B A current is induced
C Voltage is decreased
D Resistance increases
Moving a conductor through a magnetic field induces an electromotive force (EMF) and generates current, as per Faraday’s Law.
What is the unit of electrical energy?
A Joule
B Watt
C Ohm
D Volt
Electrical energy is measured in joules, representing the work done to move a charge through a potential difference.
Which type of semiconductor is formed by adding pentavalent impurities?
A N-type
B P-type
C Intrinsic
D Insulator
Adding pentavalent impurities like phosphorus creates N-type semiconductors, with electrons as majority carriers.