Question Test Series
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What is the unit of electric current?
A Volt
B Ampere
C Ohm
D Watt
B
The ampere (A) is the SI unit of electric current, defined as one coulomb per second.
What does a capacitor store?
A Charge
B Energy
C Voltage
D Current
A
A capacitor stores electric charge on its plates, creating an electric field.
What is the unit of resistance?
A Ampere
B Volt
C Ohm
D Watt
C
Resistance is measured in ohms (Ω), named after Georg Ohm’s experiments.
What is the main function of a transformer?
A Convert AC to DC
B Increase or decrease voltage
C Store energy
D Control current flow
B
A transformer changes AC voltage levels by electromagnetic induction between coils.
Which of the following is an insulator?
A Copper
B Aluminum
C Rubber
D Iron
C
Rubber does not allow electrons to flow freely, making it a good insulator.
Which component limits the current in a circuit?
A Resistor
B Capacitor
C Inductor
D Battery
A
A resistor provides resistance, thereby limiting the flow of current.
In which type of circuit is the total resistance the sum of individual resistances?
A Parallel
B Series
C Both
D None
B
In a series circuit, resistances add directly: R_total = R1 + R2 + ….
What is the unit of power?
A Ampere
B Volt
C Ohm
D Watt
D
Power is the rate of energy transfer, measured in watts (Joules per second).
What does an inductor store?
A Electric charge
B Magnetic energy
C Heat
D Light energy
B
An inductor stores energy in its magnetic field when current flows.
What is the frequency of standard AC in most countries?
A 30 Hz
B 50 Hz
C 60 Hz
D 100 Hz
B
Most countries use 50 Hz for their AC mains supply.
Which law states that the current through a conductor is directly proportional to the voltage?
A Faraday’s Law
B Ampere’s Law
C Ohm’s Law
D Lenz’s Law
C
Ohm’s Law: V = I·R, so current and voltage are proportional.
What does a diode do?
A Blocks current
B Amplifies signal
C Converts AC to DC
D Allows current in one direction
D
A diode’s p–n junction conducts current only forward, blocking reverse flow.
Which device stores energy in electric field?
A Capacitor
B Resistor
C Inductor
D Diode
A
Capacitors store energy between plates as an electric field.
Which of the following is NOT a conductor?
A Gold
B Silver
C Glass
D Copper
C
Glass has no free electrons to conduct electricity; it’s an insulator.
Which of these is a renewable source of energy?
A Coal
B Natural Gas
C Petroleum
D Solar Energy
D
Solar energy is continuously replenished by the sun, making it renewable.