Online Test — Magnetic Effects of Electric Current
20 Questions • 15 min • Chapter MCQ
15:00
Question 1 of 20
Oersted's experiment showed that an electric current produces:
heat only
a magnetic field
sound
light
Explanation: A compass deflects near a current-carrying wire.
Question 2 of 20
Magnetic field lines around a straight current-carrying wire are:
straight
concentric circles
radial
parabolic
Explanation: They form circles centred on the wire.
Question 3 of 20
In the right-hand thumb rule, the thumb points along the:
field
current
force
neutral wire
Explanation: Thumb = current, curled fingers = field.
Question 4 of 20
Outside a magnet, field lines run from:
S to N
N to S
N to N
S to S
Explanation: Outside the magnet field lines go from north to south.
Question 5 of 20
The field of a current-carrying solenoid is like that of:
a straight wire
a bar magnet
a point charge
nothing
Explanation: It has a uniform inner field with N and S ends.
Question 6 of 20
The core of an electromagnet is usually made of:
steel
soft iron
copper
aluminium
Explanation: Soft iron magnetises and demagnetises easily.
Question 7 of 20
The force on a current-carrying conductor in a magnetic field is maximum when current is:
parallel to field
perpendicular to field
zero
at 45°
Explanation: Maximum force at 90° to the field.
Question 8 of 20
Fleming's Left-Hand Rule gives the direction of:
induced current
force on a conductor
the field
resistance
Explanation: Used for the motor effect.
Question 9 of 20
In Fleming's Left-Hand Rule the forefinger represents the:
current
magnetic field
force
power
Explanation: Forefinger = field, middle = current, thumb = force.
Question 10 of 20
An electric motor converts:
mechanical to electrical energy
electrical to mechanical energy
heat to electrical energy
light to sound
Explanation: Motor: electrical to mechanical.
Question 11 of 20
The split-ring commutator in a motor:
increases voltage
reverses current every half turn
stores charge
acts as a fuse
Explanation: Reversal keeps the coil rotating one way.
Question 12 of 20
Electromagnetic induction was discovered by:
Oersted
Faraday
Ohm
Volta
Explanation: Faraday discovered induction.
Question 13 of 20
Fleming's Right-Hand Rule is used to find:
force on a wire
direction of induced current
magnetic poles
resistance
Explanation: Used in generators.
Question 14 of 20
An AC generator uses:
a split ring
slip rings
a single ring
a fuse
Explanation: Slip rings give alternating current.
Question 15 of 20
A DC generator differs from an AC generator because it uses:
slip rings
a split-ring commutator
no coil
a transformer
Explanation: The split ring keeps output in one direction.
Question 16 of 20
In a domestic circuit the live and neutral wires touching directly causes:
overloading
a short circuit
earthing
induction
Explanation: Direct contact gives near-zero resistance — a short circuit.
Question 17 of 20
A fuse protects a circuit by:
increasing current
melting and breaking the circuit on excess current
storing energy
reversing current
Explanation: Its low-melting wire melts at high current.
Question 18 of 20
The earth wire protects the user by:
raising voltage
carrying leakage current safely to the ground
blocking current
increasing resistance
Explanation: It gives a safe path to earth, preventing shocks.
Question 19 of 20
Domestic appliances are connected in:
series
parallel
a single loop
no fixed way
Explanation: Parallel gives each appliance the full voltage and independent control.
Question 20 of 20
The magnetic field at the centre of a circular coil increases when:
current decreases
number of turns increases
the field is removed
the coil is straightened
Explanation: Field is proportional to current and number of turns.