Class 10 Science Chapter 12 Practice Question Answers - Magnetic Effects of Electric Current

Ans: Magnetism.
Explanation: Magnetism is the property of materials like iron or nickel to attract or repel other materials due to their magnetic fields, caused by moving electric charges.

Ans: Magnetic field lines.
Explanation: Magnetic field lines are invisible lines that represent the direction and strength of a magnetic field around a current-carrying conductor. They form concentric circles around the wire.

Ans: Tesla (T).
Explanation: Tesla (T) is the SI unit of magnetic field strength, measuring the intensity of the magnetic field at a given point.

Ans: Strong.
Explanation: Inside a solenoid, the magnetic field is strong and uniform due to the alignment of magnetic field lines in the same direction, creating a powerful magnetic effect.

Ans: Galvanometer.
Explanation: A galvanometer is a sensitive instrument used to detect and measure small electric currents in a circuit by showing deflection on its scale.

Ans: The strength of the magnetic field increases with an increase in current.

Ans: This attraction occurs due to the alignment of magnetic domains in opposite directions, creating a stronger combined magnetic field.

Ans: Ampere's law states that the magnetic field around a closed loop is directly proportional to the electric current passing through the loop.

Ans: A soft iron core enhances the magnetic field strength in an electromagnet by providing a path for the magnetic lines of force to concentrate.

Ans: Point your thumb in the direction of the current flow, and your curled fingers indicate the direction of the magnetic field around the conductor.

Ans: An electric motor operates on the principle of electromagnetic induction. When current flows through a coil (armature) placed in a magnetic field, a force is exerted on the coil due to the interaction between the magnetic field and the current. This force causes the coil to rotate, resulting in mechanical motion.

Ans: A DC motor operates on direct current and uses a split-ring commutator to reverse the direction of current in the coil, causing continuous rotation. An AC motor operates on alternating current and doesn't require a commutator. The direction of current in the coil changes with each half-cycle, causing the rotor to turn.

Ans: An electric bell consists of an electromagnet, a hammer, and a gong. When the current flows through the coil, it generates a magnetic field that attracts the iron armature, causing the hammer to strike the gong. This interrupts the circuit, and the magnetic field collapses. The armature returns to its original position due to a spring, completing the circuit again. This cycle repeats, producing the bell's ringing sound.

Ans: According to Fleming's left-hand rule, if the forefinger, thumb, and middle finger of the left hand are held perpendicular to each other, with the forefinger representing the magnetic field direction (B), the middle finger representing the current direction (I), then the thumb indicates the direction of the force (F) experienced by the conductor.

Ans: A simple DC generator consists of a rectangular coil of wire rotating between the poles of a permanent magnet. When the coil rotates, it cuts across the magnetic field lines, inducing an electromotive force (EMF) or voltage in the coil. This EMF causes current to flow through the external circuit when the coil is connected to a load. The split-ring commutator reverses the direction of current in the coil at each half-rotation, resulting in a unidirectional current output.