What does an ammeter measure in an electrical circuit?
A Power
B Current
C Resistance
D Voltage
An ammeter is used to measure the current flowing through a circuit. It is connected in series with the circuit, so all the current passes through it. Current is measured in amperes (A).
What is the main unit used to measure electrical energy?
A Ampere
B Watt
C Joule
D Volt
Joule (J) is the unit of electrical energy. It measures the amount of work done when an electrical current flows through a circuit. One joule is equal to the energy used when one ampere of current passes through a resistor with a potential difference of one volt for one second.
What is the purpose of a capacitor in an electrical circuit?
A To store charge
B To store energy
C To limit current
D To increase voltage
A capacitor stores electrical charge in an electric field between two conductive plates separated by an insulating material. This ability to store charge makes capacitors useful in smoothing voltage fluctuations and energy storage.
Which of these materials is typically used as a conductor?
A Wood
B Rubber
C Glass
D Copper
Copper is an excellent conductor of electricity, widely used in electrical wiring and cables. It has low resistance and high conductivity, allowing efficient transmission of electrical current with minimal energy loss.
What is the unit of resistance?
A Ampere
B Watt
C Ohm
D Volt
The unit of resistance is the ohm (Ω). Resistance is a measure of how much a material opposes the flow of electric current. It depends on the material’s properties, length, and cross-sectional area.
What is the main function of a transformer in an AC circuit?
A To change voltage
B To store energy
C To change current
D To measure voltage
A transformer changes the voltage level in an AC circuit. It uses electromagnetic induction to either step up (increase) or step down (decrease) the voltage depending on the turns ratio of its coils.
Which electrical component opposes the flow of current?
A Inductor
B Resistor
C Diode
D Capacitor
A resistor opposes the flow of current by providing resistance. The higher the resistance, the more it limits the flow of electric current. Resistors are used to control current and voltage in electrical circuits.
What is the function of an inductor in a circuit?
A To limit current
B To store charge
C To store energy
D To measure voltage
An inductor stores energy in a magnetic field when current passes through it. It resists changes in the current and is commonly used in inductive components like transformers and motors.
Which device measures the voltage in a circuit?
A Ammeter
B Ohmmeter
C Wattmeter
D Voltmeter
A voltmeter is used to measure the voltage across two points in a circuit. It is connected in parallel with the component whose voltage is being measured. The unit of voltage is the volt (V).
Which of the following describes a DC current?
A Flows in one direction
B Reverses direction periodically
C Is used in household appliances
D Cannot flow through resistors
DC (Direct Current) flows in a constant direction. It is typically supplied by batteries or DC power sources. Unlike AC, DC does not reverse direction, making it suitable for many electronic devices.
What is the unit of power in an electrical circuit?
A Ampere
B Joule
C Watt
D Volt
Watt (W) is the unit of electrical power. Power is the rate at which energy is used or produced. It is calculated as the product of voltage (V) and current (I), expressed as P = V × I.
What is the principle behind an electric motor?
A Electromagnetic induction
B Magnetic field interaction
C Electric charge storage
D Voltage drop
An electric motor works on the principle of magnetic field interaction. When a current passes through a wire in a magnetic field, it experiences a force (Lorentz force), causing the wire to move. This motion is used to perform mechanical work.
Which component stores energy in a magnetic field?
A Battery
B Capacitor
C Inductor
D Resistor
An inductor stores energy in the form of a magnetic field when current flows through it. This magnetic field allows the inductor to resist changes in current and store energy, which can be released when required.
Which of the following is the unit of electrical conductance?
A Ohm
B Volt
C Siemens
D Ampere
The unit of electrical conductance is siemens (S). Conductance is the inverse of resistance and indicates how easily electricity can flow through a material. High conductance means low resistance and good current flow.
What does an electric circuit require to operate?
A Voltage
B Current
C Resistance
D Grounding
An electric circuit requires voltage to operate. Voltage (electrical potential difference) is necessary to drive the current through the circuit. Without voltage, the flow of electrical charge (current) cannot occur.