Which device converts electrical energy into mechanical energy?
A Generator
B Transformer
C Battery
D Motor
An electric motor converts electrical energy into mechanical energy by utilizing electromagnetic principles to produce motion.
What is the SI unit of electric current?
A Ampere
B Ohm
C Volt
D Watt
The SI unit of electric current is the Ampere (A). It measures the flow of electric charge per unit time. One Ampere is defined as one Coulomb of charge passing through a point in one second.
Which law states that the sum of voltages around a closed loop is zero?
A Faraday’s Law
B Kirchhoff’s Voltage Law
C Coulomb’s Law
D Ohm’s Law
Kirchhoff’s Voltage Law (KVL) states that the algebraic sum of all voltages around a closed loop in a circuit is zero, ensuring energy conservation.
What is the unit of electrical resistance?
A Ohm
B Volt
C Ampere
D Joule
The unit of electrical resistance is the Ohm (Ω). It measures the opposition to the flow of electric current in a conductor.
Which of the following is a semiconductor material?
A Silicon
B Copper
C Aluminum
D Silver
Silicon is a semiconductor material widely used in electronic devices due to its ability to conduct electricity under certain conditions and act as an insulator under others.
Which material is the best conductor of electricity?
A Rubber
B Wood
C Glass
D Copper
Copper is an excellent conductor of electricity due to its high free electron density and low resistance. It is widely used in electrical wiring and components.
What is the primary function of a resistor in an electrical circuit?
A Store energy
B Generate voltage
C Control current flow
D Measure power
A resistor is used to limit or control the flow of electric current in a circuit. It provides resistance, which opposes the flow of electrons, thereby regulating current and voltage levels.
Which law states that the current through a conductor is directly proportional to the voltage across it?
A Kirchhoff’s Voltage Law
B Ohm’s Law
C Faraday’s Law
D Coulomb’s Law
Ohm’s Law states that V = I R, where V is voltage, I is current, and R is resistance. It describes the relationship between voltage, current, and resistance in a conductor.
What is the purpose of a fuse in an electrical circuit?
A Increase current flow
B Store energy
C Measure voltage
D Protect against overcurrent
A fuse is a safety device that protects electrical circuits by melting and breaking the circuit when the current exceeds a safe level, preventing damage or fire.
What is the role of an insulator in an electrical system?
A Store electricity
B Block electricity
C Generate electricity
D Conduct electricity
Insulators are materials that resist the flow of electric current. They are used to prevent unwanted current flow and ensure safety in electrical systems.
What does Kirchhoff’s Current Law (KCL) state?
A The sum of voltages in a loop is zero.
B The current in a circuit is proportional to voltage.
C The sum of currents entering a junction equals the sum leaving it.
D The power in a circuit is conserved.
Kirchhoff’s Current Law (KCL) states that the total current entering a junction in a circuit must equal the total current leaving it, ensuring charge conservation.
Which of the following is a passive electrical component?
A Diode
B Resistor
C Transistor
D Battery
A resistor is a passive component because it does not generate energy. It only consumes or dissipates energy in the form of heat.
Which of the following is a renewable energy source?
A Coal
B Nuclear power
C Solar power
D Natural gas
Solar power is a renewable energy source that harnesses energy from the sun using photovoltaic cells or solar panels, making it sustainable and environmentally friendly.
What is the formula for electrical power?
A P = I R
B P = V / R
C P = V I
D P = V / R
Electrical power is calculated using the formula P = V I, where P is power in watts, V is voltage in volts, and I is current in amperes.
What is the direction of conventional current flow in a circuit?
A Positive to negative
B Negative to positive
C Random direction
D No specific direction
Conventional current flow is defined as the flow of positive charge from the positive terminal to the negative terminal of a power source.
What is the charge of a single electron?
A +1.6 × 10-19 C
B -1.6 × 10-19 C
C +1 C
D 0 C
The charge of an electron is negative and has a magnitude of -1.6 × 10-19 C, a fundamental constant in physics and electrical engineering.
What does an ammeter measure?
A Voltage
B Resistance
C Current
D Power
An ammeter is a device used to measure electric current in a circuit. It is connected in series to ensure accurate readings.
What is the reciprocal of resistance called?
A Voltage
B Conductance
C Inductance
D Capacitance
Conductance, denoted by G, is the reciprocal of resistance and is measured in siemens (S). It represents how easily current flows through a material.
Which of the following is a property of an insulator?
A High conductivity
B Low resistance
C High resistance
D Free-flowing electrons
Insulators have very high resistance, making them poor conductors of electricity. Materials like rubber and glass are examples.
Which device is used to measure resistance?
A Ammeter
B Voltmeter
C Ohmmeter
D Wattmeter
An ohmmeter is designed to measure the resistance of a component or circuit by passing a small current through it.
What is the relationship between power, voltage, and resistance?
A P = V² / R
B P = R / V²
C P = VI
D P = IR
Using Ohm’s law (V = IR) and the power formula (P = VI), power can also be expressed as P = V² / R.
Which material is commonly used as a semiconductor?
A Copper
B Silicon
C Rubber
D Aluminum
Silicon is the most widely used semiconductor material due to its abundance, stable properties, and ability to be doped with impurities.
What is the SI unit of electric field strength?
A Tesla
B Newton per coulomb
C Volt per ampere
D Ohm per meter
Electric field strength is measured in newtons per coulomb (N/C), representing the force per unit charge.
What does a diode do in a circuit?
A Stores energy
B Allows current in one direction
C Resists current flow
D Increases voltage
A diode allows current to flow in only one direction and blocks it in the reverse direction, functioning as a one-way valve.
What type of current does a generator produce?
A Alternating Current (AC)
B Direct Current (DC)
C Both AC and DC
D Pulsating Current
Generators typically produce alternating current (AC), which is used for most electrical power distribution systems.
What is the formula for calculating capacitance?
A C = Q / V
B C = V / Q
C C = V × Q
D C = V² / Q
Capacitance (C) is the ratio of the charge (Q) stored on the plates of a capacitor to the voltage (V) across it. The formula is C = Q / V.
What happens when an inductor is connected to an AC source?
A It resists the change in current.
B It blocks the current.
C It acts as a short circuit.
D It stores energy as charge.
An inductor opposes changes in current by generating a back electromotive force (EMF), which resists the alternating current.
What is the primary purpose of a transformer?
A To change the frequency of AC
B To increase or decrease voltage
C To convert AC to DC
D To store energy
A transformer transfers electrical energy between circuits and modifies voltage levels based on the number of turns in its coils.
What does the term “electric flux” refer to?
A The flow of electric current
B The total electric field passing through a surface
C The resistance of a conductor
D The potential energy in a circuit
Electric flux represents the total electric field lines passing through a given surface, measured in N·m²/C.
What is the key principle behind solar cells?
A Electromagnetic induction
B Photoelectric effect
C Ohm’s law
D Magnetic flux
Solar cells operate based on the photoelectric effect, where light photons generate an electric current in a semiconductor material.
What is the role of a transformer in an electrical system?
A Step up or step down voltage
B Convert AC to DC
C Store electrical energy
D Measure current
A transformer is used to increase (step-up) or decrease (step-down) voltage levels in an AC system. It operates on the principle of electromagnetic induction.
What is the primary purpose of a capacitor in a circuit?
A Measure current
B Generate electrical energy
C Block current flow
D Store electrical energy
A capacitor stores electrical energy in an electric field. It consists of two conductive plates separated by an insulator and is used in circuits for energy storage, filtering, and timing applications.
Which of the following is a characteristic of a DC system?
A Current changes direction
B Frequency is 50 Hz
C Voltage is constant
D Used in transformers
In a DC (Direct Current) system, the voltage remains constant over time, and the current flows in a single direction, unlike AC (Alternating Current), where both voltage and current change direction periodically.
What is the function of a diode in a circuit?
A Amplify signals
B Allow current in one direction
C Store energy
D Measure voltage
A diode is a semiconductor device that allows current to flow in one direction only. It is commonly used for rectification, converting AC to DC.
What is the unit of electrical energy?
A Volt
B Joule
C Ampere
D Ohm
The unit of electrical energy is the Joule (J). It represents the amount of work done when a force of one Newton moves an object one meter. In electrical terms, it is the energy consumed when one Ampere flows through one Ohm for one second.
What is the unit of electric potential?
A Watt
B Ampere
C Ohm
D Volt
The unit of electric potential is the Volt (V). It represents the potential energy per unit charge and is a measure of the work done to move a charge between two points.
What is the SI unit of electric charge?
A Coulomb
B Volt
C Ampere
D Ohm
The SI unit of electric charge is the Coulomb (C). It represents the quantity of electricity transported by a current of one Ampere in one second.
What is the relationship between power, voltage, and current?
A P = V^2 / I
B P = V I
C P = V / I^2
D P = V / I
The relationship between power (P), voltage (V), and current (I) is given by P = V I. Power is the product of voltage and current and is measured in watts.
Which law describes the force between two electric charges?
A Ohm’s Law
B Faraday’s Law
C Kirchhoff’s Law
D Coulomb’s Law
Coulomb’s Law describes the electrostatic force between two charged objects. It states that the force is directly proportional to the product of the charges and inversely proportional to the square of the distance between them.
Which of the following is a characteristic of an AC system?
A Frequency is 50 Hz or 60 Hz
B Current flows in one direction
C Voltage is constant
D Used in batteries
In an AC (Alternating Current) system, the voltage and current change direction periodically. The frequency of this change is typically 50 Hz or 60 Hz, depending on the region.
Which of the following is a renewable energy source?
A Coal
B Wind energy
C Natural gas
D Nuclear energy
Wind energy is a renewable energy source that harnesses the kinetic energy of wind to generate electricity using wind turbines. It is sustainable and environmentally friendly.
Which of the following is a safety measure in electrical systems?
A Increasing voltage
B Using high resistance
C Grounding
D Using copper wires
Grounding is a safety measure that provides a path for excess electric current to flow into the earth, preventing electric shock, fires, and damage to equipment.
Which of the following is an example of an insulator?
A Rubber
B Copper
C Aluminum
D Silver
Rubber is an insulator because it has very high resistance and does not allow electric current to flow through it. It is commonly used to coat wires for safety.
Which device is used to measure electric current?
A Voltmeter
B Ohmmeter
C Ammeter
D Wattmeter
An ammeter is a device used to measure electric current in a circuit. It is connected in series with the circuit to measure the flow of current in amperes.
What is the primary function of a switch in a circuit?
A Store energy
B Generate power
C Control current flow
D Measure voltage
A switch is used to control the flow of current in a circuit by opening (breaking) or closing (completing) the circuit. It is a fundamental component in electrical systems.
What is the purpose of a circuit breaker?
A Store energy
B Generate power
C Protect against overcurrent
D Measure resistance
A circuit breaker is a safety device that automatically interrupts the flow of current in a circuit when it exceeds a safe level, preventing damage or fire.
Which of the following is a characteristic of a parallel circuit?
A Single current path
B Components are dependent
C Same current through components
D Same voltage across components
In a parallel circuit, the voltage across all components is the same, but the current divides among the branches. The total resistance is less than the smallest individual resistance.
What is the unit of inductance?
A Ohm
B Henry
C Farad
D Tesla
The unit of inductance is the Henry (H). It measures the ability of a coil to store energy in a magnetic field when current flows through it.
What is the unit of electrical conductivity?
A Siemens
B Ohm
C Volt
D Ampere
The unit of electrical conductivity is Siemens (S). It is the reciprocal of resistance and measures how easily electric current can flow through a material. Higher conductivity means lower resistance.
What is the unit of magnetic flux?
A Tesla
B Gauss
C Henry
D Weber
The unit of magnetic flux is the Weber (Wb). It represents the total magnetic field passing through a given area and is a measure of the strength of the magnetic field.