Online Test — Magnetism and Electromagnetism
25 Questions • 15 min • Chapter MCQ
15:00
Question 1 of 25
The region around a magnet where its force can be detected is the:
Electric field
Magnetic field
Gravitational field
Pole
Explanation: The magnetic field is the region around a magnet where its force acts.
Question 2 of 25
Like poles of two magnets:
Attract
Repel
Do nothing
Melt
Explanation: Like poles repel; unlike poles attract.
Question 3 of 25
Outside a magnet, magnetic field lines point from the:
South to north pole
North to south pole
East to west
Top to bottom
Explanation: Outside the magnet, field lines run from the north pole to the south pole.
Question 4 of 25
A magnetic field is strong where the field lines are:
Far apart
Crowded close together
Crossing
Straight
Explanation: Crowded (close) field lines indicate a strong field, as near the poles.
Question 5 of 25
Two magnetic field lines can never:
Be curved
Cross each other
Form loops
Point to a pole
Explanation: Field lines never cross, since the field has only one direction at each point.
Question 6 of 25
Oersted's experiment showed that an electric current produces a:
Sound
Magnetic field
Light beam
Vacuum
Explanation: Oersted showed that a current produces a magnetic field around it.
Question 7 of 25
In Oersted's experiment, the compass needle was ______ when current flowed.
Melted
Deflected
Destroyed
Cooled
Explanation: The compass needle was deflected, showing the current's magnetic field.
Question 8 of 25
The magnetic field lines around a straight current-carrying wire are:
Straight lines
Concentric circles
Squares
Triangles
Explanation: The field lines form concentric circles around a straight wire.
Question 9 of 25
The rule used to find the direction of the field around a wire is the:
Ohm's law
Right-hand thumb rule
Pascal's law
Snell's law
Explanation: The right-hand thumb rule gives the direction of the magnetic field.
Question 10 of 25
The magnetic field around a wire is stronger when the current is:
Smaller
Larger
Zero
Reversed only
Explanation: A larger current produces a stronger magnetic field around the wire.
Question 11 of 25
A coil of many circular turns of insulated wire wound like a cylinder is a:
Resistor
Solenoid
Fuse
Capacitor
Explanation: A solenoid is a coil of many turns wound in the shape of a cylinder.
Question 12 of 25
The magnetic field of a current-carrying solenoid is similar to that of a:
Straight wire
Bar magnet
Battery
Bulb
Explanation: A current-carrying solenoid produces a field like that of a bar magnet.
Question 13 of 25
An electromagnet is made by winding a coil around a core of:
Soft iron
Wood
Plastic
Glass
Explanation: An electromagnet uses a soft iron core, which magnetises and demagnetises easily.
Question 14 of 25
An electromagnet loses its magnetism when the:
Current is switched off
Coil is added
Core is iron
Turns increase
Explanation: An electromagnet is a temporary magnet; it loses magnetism when the current stops.
Question 15 of 25
Which of these increases the strength of an electromagnet?
Fewer turns
Increasing the current
Removing the core
Reducing the current
Explanation: Increasing the current (or turns, or using a soft iron core) strengthens it.
Question 16 of 25
A current-carrying conductor placed in a magnetic field experiences a:
Force
Sound
Smell
Colour change
Explanation: The interaction of the fields makes the conductor experience a force.
Question 17 of 25
The direction of the force on a current-carrying conductor is given by:
Right-hand thumb rule
Fleming's left-hand rule
Ohm's law
Snell's law
Explanation: Fleming's left-hand rule gives the direction of the force.
Question 18 of 25
In Fleming's left-hand rule, the thumb represents the:
Field
Current
Force (motion)
Resistance
Explanation: The thumb represents the force (direction of motion).
Question 19 of 25
An electric motor converts electrical energy into ______ energy.
Sound
Mechanical (kinetic)
Chemical
Light
Explanation: A motor converts electrical energy into mechanical (kinetic) energy.
Question 20 of 25
The split ring that reverses the current each half turn in a DC motor is the:
Brush
Commutator
Armature
Magnet
Explanation: The commutator reverses the current each half turn to keep the coil rotating.
Question 21 of 25
The production of a current in a coil by a changing magnetic field is called:
Conduction
Electromagnetic induction
Reflection
Electrolysis
Explanation: Electromagnetic induction is producing a current with a changing magnetic field.
Question 22 of 25
A current is induced in a coil only when the magnetic field through it is:
Constant
Changing
Zero
Removed completely
Explanation: Induction requires a changing magnetic field; a steady field induces no current.
Question 23 of 25
An electric generator converts ______ energy into electrical energy.
Chemical
Mechanical (kinetic)
Sound
Light
Explanation: A generator converts mechanical (kinetic) energy into electrical energy.
Question 24 of 25
A transformer that increases the voltage is a:
Step-down transformer
Step-up transformer
Motor
Generator
Explanation: A step-up transformer increases the voltage.
Question 25 of 25
The transformer relation between voltage and turns is:
Vₚ/Vₛ = Nₚ/Nₛ
V = IR
P = VI
F = ma
Explanation: A transformer obeys Vₚ/Vₛ = Nₚ/Nₛ.