Q1:
Question for Assertion & Reason Type Questions: Magnetic Effects of Current
Try yourself: Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : Safety fuses are made up of materials having a low melting point.
Reason : Safety fuses should be resistant to electric current.
Explanation
Safety fuses are made up of materials having a low melting point so that when excess current flows through the circuit, the fuse melts breaking the circuit and thus prevents appliances.
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Q2:
Question for Assertion & Reason Type Questions: Magnetic Effects of Current
Try yourself: Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : Copper is used to make electric wires.
Reason : Copper has very low electrical resistance.
Explanation
The low electrical resistance of copper makes it a good conductor for electricity.
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Q3:
Question for Assertion & Reason Type Questions: Magnetic Effects of Current
Try yourself: Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : AC load line is used for long distance transmission.
Reason : It has very less loss of energy in long distance transmission.
Explanation
It can be easily transmitted over long distances without much loss in energy.
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Q4:
Question for Assertion & Reason Type Questions: Magnetic Effects of Current
Try yourself: Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : The magnitude o f the magnetic field at a point on the axis of a current carrying solenoid is inversely proportional to the current flowing through the solenoid.
Reason : The magnitude of the magnetic field at a point on the axis of a current carrying solenoid is directly proportional to the number of turns per unit length of a solenoid.
Explanation
The magnetic field inside a solenoid is proportional to both the applied current and the number of turns per unit length. There is no dependence on the diameter of the solenoid, and the field strength doesn't depend on the position inside the solenoid, i.e., the field inside is constant.
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Q5:
Question for Assertion & Reason Type Questions: Magnetic Effects of Current
Try yourself: Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : The magnetic field produced by current carrying solenoid is independent of its length and cross-section area.
Reason : The magnetic field inside the solenoid is uniform.
Explanation
The magnetic field is independent of length and area. It is uniform inside the solenoid.
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Q6:
Question for Assertion & Reason Type Questions: Magnetic Effects of Current
Try yourself: Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion: A solenoid tends to expand, when a current passes through it.
Reason : Two straight parallel metallic wires carrying current in the same direction attract each other.
Explanation
When current flows through a solenoid, the currents in the various turns of the solenoid are parallel and in the same direction. Since the current flowing through parallel wires in the same direction leads to force of attraction between them, the turns of the solenoid will also attract each other and as a result the solenoid tends to contract.
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Q7:
Question for Assertion & Reason Type Questions: Magnetic Effects of Current
Try yourself: Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : Force experienced by moving charge will be maximum if direction of velocity of charge is perpendicular to applied magnetic field.
Reason : Force on moving charge is independent of direction of applied magnetic field.
Explanation
From equation F — qvBsin?. Force on moving charge will be maximum if direction of velocity of charge is perpendicular to direction of magnetic field (when 6 = 90°)
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Q8:
Question for Assertion & Reason Type Questions: Magnetic Effects of Current
Try yourself: Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : There is no change in the energy of a charged particle moving in a magnetic field although a magnetic force is acting on it.
Reason : Work done by centripetal force is always zero.
Explanation
Magnetic force is always perpendicular to the direction of motion of charged particle, i.e., work done on the charge particle moving on a circular path in magnetic field zero.
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Q9:
Question for Assertion & Reason Type Questions: Magnetic Effects of Current
Try yourself: Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : In a conductor, free electrons keep on moving but no magnetic force acts on a conductor in a magnetic field.
Reason : Force on free electrons due to magnetic field always acts perpendicular to its direction of motion.
Explanation
In a conductor, the average velocity of electrons is zero. Hence no current flows through the conductor. Hence, no force acts on this conductor.
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Q10:
Question for Assertion & Reason Type Questions: Magnetic Effects of Current
Try yourself: Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : A current carrying conductor experiences a force in a magnetic field.
Reason : The force acting on a current carrying conductor in a magnetic field is due to interaction between the magnetic field produced by the current carrying conductor and the external magnetic field in which the conductor is placed.
Explanation
When a current carrying conductor is placed in a magnetic field, it experiences a force except when it is placed parallel to the magnetic field. The force acting on a current carrying conductor in a magnetic field is due to interaction between the magnetic field produced by the current carrying conductor and the external magnetic field in which the conductor is placed.
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Q11:
Question for Assertion & Reason Type Questions: Magnetic Effects of Current
Try yourself: Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : On changing the direction of flow of current through a straight conductor, the direction of a magnetic field around the conductor is reversed.
Reason : The direction of the magnetic field around a conductor can be given in accordance with the left hand thumb rule.
Explanation
(i) The strength of magnetic field around a straight current conductor increases
on increasing the strength of current in the conductor or vice versa.
(ii)The direction of the magnetic field around a straight current carrying conductor gets reversed if the direction of current through that conductor is reversed.
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Q12:
Question for Assertion & Reason Type Questions: Magnetic Effects of Current
Try yourself: Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : Magnetic field lines never intersect.
Reason : At a particular point the magnetic field has only one direction.
Explanation
If magnetic field lines intersect each other, then at the intersection point there will be two directions of the same field which is not possible. Hence the field lines do not cross or intersect each other.
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Q13:
Question for Assertion & Reason Type Questions: Magnetic Effects of Current
Try yourself: Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : A compass needle is placed near a current carrying wire. The deflection of the compass needle decreases when the compass needle is displaced away from the wire.
Reason : Strength of a magnetic field decreases as one moves away from a current carrying conductor.
Explanation
If the current is increased in the conductor the deflection of the compass needle increases. This is because the strength of the magnetic field varies directly as the magnitude of the electric current, or the current passing through the wire.
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Q14:
Question for Assertion & Reason Type Questions: Magnetic Effects of Current
Try yourself: Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : The magnetic field is stronger at a point which is nearer to the conductor and goes on decreasing on moving away from the conductor.
Reason : The magnetic field B produced by a straight current carrying wire is inversely proportional to the distance from the wire.
Explanation
The magnitude of the magnetic field is
1. directly proportional to the current I passing through the wire.
2. Inversely proportional to the distance r from the wire. The magnetic field is stronger at a point that is nearer to the conductor and goes on decreasing on moving away from the conductor.
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Q15:
Question for Assertion & Reason Type Questions: Magnetic Effects of Current
Try yourself: Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion : an induced current has a direction such that the magnetic flux that induces the current.
Reason : Above statement is in accordance with conservation of energy.
Explanation
According to Lenz's Law, the current is induced in such a direction that it opposes the change in magnetic flux linked with the coil.
Lenz's law is in accordance with the Principle of Conservation of Energy.
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