Q.1 What is the unit of electric current?
Volt
Ampere
Ohm
Coulomb
Explanation - Electric current is measured in amperes (A), which represent the flow of charge per unit time.
Correct answer is: Ampere
Q.2 Which particle is responsible for electric current in metals?
Protons
Neutrons
Electrons
Ions
Explanation - Electrons are free to move in metals and carry the electric current.
Correct answer is: Electrons
Q.3 Ohm's law states that:
V = IR
P = VI
Q = It
E = mc²
Explanation - Ohm's law relates voltage (V), current (I), and resistance (R) as V = IR.
Correct answer is: V = IR
Q.4 The SI unit of resistance is:
Coulomb
Ampere
Ohm
Henry
Explanation - Resistance is measured in ohms (Ω).
Correct answer is: Ohm
Q.5 What does a voltmeter measure?
Current
Resistance
Voltage
Power
Explanation - A voltmeter is used to measure potential difference (voltage) across a component.
Correct answer is: Voltage
Q.6 Which rule gives the direction of current in a generator?
Right-hand thumb rule
Fleming’s left-hand rule
Fleming’s right-hand rule
Lenz’s law
Explanation - Fleming’s right-hand rule determines the direction of induced current in a generator.
Correct answer is: Fleming’s right-hand rule
Q.7 In a series circuit, the current is:
Same through all components
Different in each component
Maximum at the start
Zero at the end
Explanation - In a series circuit, the same current flows through all components.
Correct answer is: Same through all components
Q.8 Which device is used to convert AC to DC?
Motor
Transformer
Rectifier
Generator
Explanation - Rectifiers convert alternating current (AC) into direct current (DC).
Correct answer is: Rectifier
Q.9 Magnetic field lines around a straight current-carrying conductor are:
Straight lines
Concentric circles
Random
Parallel lines
Explanation - The magnetic field around a straight conductor forms concentric circles.
Correct answer is: Concentric circles
Q.10 Which material is most commonly used in electrical wiring?
Aluminum
Copper
Iron
Silver
Explanation - Copper is widely used because it has high conductivity and is relatively cheap.
Correct answer is: Copper
Q.11 The power consumed in a circuit is given by:
P = VI
P = IR
P = I²R
Both P = VI and P = I²R
Explanation - Power can be expressed as P = VI or, using Ohm’s law, P = I²R.
Correct answer is: Both P = VI and P = I²R
Q.12 Who discovered the electron?
Newton
Faraday
Thomson
Coulomb
Explanation - J.J. Thomson discovered the electron in 1897.
Correct answer is: Thomson
Q.13 What is the function of a fuse in an electric circuit?
To increase current
To decrease resistance
To protect from overcurrent
To store charge
Explanation - A fuse melts and breaks the circuit when current exceeds a safe limit.
Correct answer is: To protect from overcurrent
Q.14 The direction of magnetic field inside a solenoid is:
Circular
Parallel to axis
Random
Opposite to current
Explanation - Inside a solenoid, the magnetic field is uniform and parallel to the axis.
Correct answer is: Parallel to axis
Q.15 Which law explains the relationship between induced emf and change in magnetic flux?
Ohm’s law
Faraday’s law
Lenz’s law
Ampere’s law
Explanation - Faraday’s law states that induced emf is proportional to the rate of change of magnetic flux.
Correct answer is: Faraday’s law
Q.16 What is the SI unit of magnetic field strength?
Tesla
Weber
Gauss
Ampere-turn
Explanation - Magnetic field strength is measured in Tesla (T).
Correct answer is: Tesla
Q.17 When two like charges are brought near each other, they:
Attract
Repel
Stay neutral
Form a dipole
Explanation - Like charges repel each other, unlike charges attract.
Correct answer is: Repel
Q.18 Which instrument measures electric current?
Voltmeter
Ammeter
Galvanometer
Wattmeter
Explanation - An ammeter is used to measure current in a circuit.
Correct answer is: Ammeter
Q.19 What type of current is supplied to homes?
AC
DC
Both AC and DC
Static electricity
Explanation - Alternating current (AC) is supplied to homes as it can be easily transmitted over long distances.
Correct answer is: AC
Q.20 The device used to store electric charge is:
Resistor
Capacitor
Inductor
Transformer
Explanation - A capacitor stores electrical energy in the form of an electric field.
Correct answer is: Capacitor
Q.21 Which scientist showed that current-carrying conductors produce magnetic fields?
Coulomb
Oersted
Faraday
Ampere
Explanation - Hans Christian Oersted discovered that electric currents produce magnetic fields in 1820.
Correct answer is: Oersted
Q.22 The time taken for one complete cycle of AC is called:
Frequency
Period
Wavelength
Amplitude
Explanation - The time for one cycle of AC is its period; frequency is the reciprocal of period.
Correct answer is: Period
Q.23 Coulomb’s law deals with:
Gravitational force
Electrostatic force
Magnetic force
Nuclear force
Explanation - Coulomb’s law describes the force between two electric charges.
Correct answer is: Electrostatic force
Q.24 Which device increases or decreases AC voltage?
Rectifier
Capacitor
Transformer
Diode
Explanation - Transformers are used to step up or step down AC voltages.
Correct answer is: Transformer
Q.25 Which type of magnet is used in electromagnets?
Permanent magnet
Soft iron core
Steel core
Alloys of iron
Explanation - Soft iron cores are used because they can be easily magnetized and demagnetized.
Correct answer is: Soft iron core