Case Description:
Electromagnets are created when an electric current flows through a coil of
wire, producing a magnetic field. The strength of the magnetic field can be
increased by increasing the number of turns in the coil, the amount of current
flowing through it, or by using a ferromagnetic core.
MCQs:
What is the primary factor that affects the strength of an electromagnet?
When a ferromagnetic core is placed inside a coil of wire carrying current, what happens to the strength of the magnetic field?
Which of the following materials is commonly used as a core for an electromagnet?
In which of the following applications are electromagnets commonly used?
Case Description:
When an electric current flows through a straight conductor, it produces a
magnetic field around it. The direction of the magnetic field can be determined
using the right-hand thumb rule, which states that if you hold the conductor
with your right hand such that your thumb points in the direction of the
current, your curled fingers show the direction of the magnetic field lines.
MCQs:
According to the right-hand thumb rule, if the current flows upwards in a vertical conductor, in which direction will the magnetic field lines circulate?
What is the shape of the magnetic field lines around a straight current-carrying conductor?
What happens to the strength of the magnetic field if the current flowing through the conductor is doubled?
Which instrument is used to detect the presence of a magnetic field around a current-carrying conductor?
Case Description:
A current-carrying conductor placed in a magnetic field experiences a force.
This principle is the basis for the operation of electric motors. The direction
of the force can be determined using Fleming's left-hand rule, which states that
if the thumb, forefinger, and middle finger are held at right angles to each
other, the thumb indicates the direction of the force, the forefinger indicates
the direction of the magnetic field, and the middle finger indicates the
direction of the current.
MCQs:
According to Fleming's left-hand rule, what does the thumb represent?
If a current-carrying conductor is placed perpendicular to a magnetic field, what will happen to it?
The force acting on a current-carrying conductor in a magnetic field is dependent on which of the following factors?
If the direction of the current in the conductor is reversed, what happens to the direction of the force experienced by the conductor?
Case Description:
An electric motor converts electrical energy into mechanical energy using the
interaction between a magnetic field and a current-carrying coil. The coil
rotates due to the forces acting on it, which are a result of the magnetic field
produced by the permanent magnets or electromagnets within the motor.
MCQs:
What is the main component of an electric motor that rotates?
What principle does an electric motor operate on?
Which of the following is responsible for reversing the direction of current in the coil of an electric motor?
In a simple electric motor, what happens when the switch is turned off?
Case Description:
A solenoid is a long coil of wire wound in the shape of a cylinder. When an
electric current passes through it, a uniform magnetic field is produced inside
the solenoid, resembling that of a bar magnet. The strength of the magnetic
field can be increased by increasing the number of turns in the coil, increasing
the current, or by inserting a ferromagnetic core.
MCQs:
What is the shape of the magnetic field lines inside a solenoid?
How does the magnetic field outside a solenoid compare to that inside?
What will happen to the magnetic field strength inside a solenoid if the current flowing through it is doubled?
In practical applications, solenoids are often used in: