Question 1

In a domestic electric circuit, what is the purpose of the earth wire?

Accepted Answer

Correct Option: C. Solution: The earth wire is used as a safety measure to prevent electric shocks. It provides a low-resistance path for any leakage current, ensuring that the potential of the appliance remains at the earth's potential.

Question 2

What happens to the direction of the compass needle when the direction of current in a nearby wire is reversed?

Accepted Answer

Correct Option: B. Solution: When the direction of current is reversed, the magnetic field direction is also reversed, causing the compass needle to deflect in the opposite direction.

Question 3

A current-carrying conductor is placed in a magnetic field directed upwards. If the current flows from end B to end A of the conductor, in which direction will the conductor be displaced?

Accepted Answer

Correct Option: A. Solution: When the current flows from end B to end A and the magnetic field is directed upwards, the conductor is displaced to the left.

Question 4

A current-carrying straight conductor is placed vertically. If the current flows upwards, what is the direction of the magnetic field at a point directly east of the conductor?

Accepted Answer

Correct Option: B. Solution: Using the right-hand thumb rule, if the current flows upwards, the fingers curl in the direction of the magnetic field. At a point directly east, the field points towards the south.

Question 5

What happens when the live wire and neutral wire come into direct contact in a domestic circuit?

Accepted Answer

Correct Option: C. Solution: When the live wire and neutral wire come into contact, it causes a short circuit, leading to a sudden increase in current. This can cause overheating and damage to the circuit if not protected by a fuse.

Question 6

Why don't two magnetic field lines intersect each other?

Accepted Answer

Correct Option: B. Solution: Magnetic field lines do not intersect because at the point of intersection, the compass needle would point in two different directions, which is not possible.

Question 7

A circular loop of wire is placed in the plane of the table and a current is passed through it in a clockwise direction. Using the right-hand rule, what is the direction of the magnetic field inside the loop?

Accepted Answer

Correct Option: B. Solution: According to the right-hand rule, if the current flows clockwise in the loop, the magnetic field inside the loop is directed downward, perpendicular to the plane of the loop.

Question 8

What happens to the deflection of a compass needle when the current in a nearby copper wire is increased?

Accepted Answer

Correct Option: C. Solution: The deflection of the compass needle increases as the current through the wire increases, indicating a stronger magnetic field.

Question 9

What happens to the current in a domestic circuit during a short circuit?

Accepted Answer

Correct Option: C. Solution: During a short circuit, the resistance drops significantly, causing a heavy increase in current.

Question 10

In a domestic electric circuit, what is the function of the earth wire?

Accepted Answer

Correct Option: C. Solution: The earth wire provides a low-resistance path for current leakage, preventing electric shocks by keeping the potential of the appliance's body at earth potential.

Question 11

According to Oersted's observation, what is the relationship between electricity and magnetism?

Accepted Answer

Correct Option: B. Solution: Oersted discovered that an electric current passing through a wire produces a magnetic field, showing that electricity can produce magnetism.

Question 12

Which rule helps determine the direction of the magnetic field around a current-carrying conductor?

Accepted Answer

Correct Option: B. Solution: The right-hand thumb rule helps determine the direction of the magnetic field around a current-carrying conductor.

Question 13

What happens to the direction of the magnetic field when the direction of current through a straight wire is reversed?

Accepted Answer

Correct Option: B. Solution: When the direction of current through a straight wire is reversed, the direction of the magnetic field is also reversed.

Question 14

Which rule is used to determine the direction of force on a current-carrying conductor in a magnetic field?

Accepted Answer

Correct Option: B. Solution: Fleming's left-hand rule is used to determine the direction of force on a current-carrying conductor in a magnetic field.

Question 15

A current-carrying conductor is placed in a magnetic field such that the direction of the current is perpendicular to the direction of the magnetic field. According to Fleming's left-hand rule, what is the direction of the force acting on the conductor?

Accepted Answer

Correct Option: B. Solution: According to Fleming's left-hand rule, if the forefinger points in the direction of the magnetic field and the second finger in the direction of the current, then the thumb will point in the direction of the force acting on the conductor, which is perpendicular to both the magnetic field and the current.

Question 16

A positively-charged particle projected towards the west is deflected towards the north by a magnetic field. What is the direction of the magnetic field?

Accepted Answer

Correct Option: D. Solution: The magnetic field is directed upward to cause a deflection of a positively-charged particle towards the north when projected towards the west.

Question 17

According to the right-hand thumb rule, if the current flows upwards through a vertical conductor, in which direction do the magnetic field lines circulate?

Accepted Answer

Correct Option: B. Solution: According to the right-hand thumb rule, if the current flows upwards, the fingers curl in a counterclockwise direction around the conductor indicating the direction of the magnetic field lines.

Question 18

What happens to the magnetic field strength when the current through a straight conductor is increased?

Accepted Answer

Correct Option: C. Solution: The magnetic field strength increases as the current through a straight conductor is increased, as indicated by the greater deflection of a compass needle.

Question 19

Which of the following correctly describes the magnetic field near a long straight wire?

Accepted Answer

Correct Option: D. Solution: The magnetic field around a long straight wire consists of concentric circles centered on the wire.

Question 20

According to the right-hand thumb rule, if the thumb points in the direction of current, what do the fingers represent?

Accepted Answer

Correct Option: B. Solution: According to the right-hand thumb rule, if the thumb points in the direction of current, the fingers wrap around in the direction of the magnetic field lines.

Question 21

A circular coil with multiple turns is placed in a uniform magnetic field. How does the magnetic field strength inside the coil compare to that of a single loop?

Accepted Answer

Correct Option: C. Solution: The magnetic field strength inside a coil with multiple turns is stronger than that of a single loop because the field produced by each turn adds up, resulting in a cumulative effect.

Question 22

How does the magnetic field inside a long straight solenoid-carrying current behave?

Accepted Answer

Correct Option: D. Solution: The magnetic field inside a long straight solenoid-carrying current is uniform and the same at all points.

Question 23

Which wire in a domestic circuit is typically insulated with red color?

Accepted Answer

Correct Option: B. Solution: In domestic circuits, the live wire is usually insulated with red color to indicate it carries current.

Question 24

In the context of magnetic field lines, what does the closeness of the lines indicate?

Accepted Answer

Correct Option: A. Solution: The closeness of magnetic field lines indicates the strength of the magnetic field; closer lines represent a stronger field.

Question 25

What is the pattern of the magnetic field lines inside a long straight solenoid carrying current?

Accepted Answer

Correct Option: D. Solution: Inside a long straight solenoid, the magnetic field is uniform and the same at all points.

Question 26

What is the primary function of a solenoid when a current passes through it?

Accepted Answer

Correct Option: A. Solution: A solenoid creates a uniform magnetic field inside it when a current passes through, similar to a bar magnet.

Question 27

A compass needle is placed near a long straight copper wire carrying a current from north to south. What will be the direction of deflection of the north pole of the compass needle?

Accepted Answer

Correct Option: A. Solution: When the current flows from north to south, the magnetic field around the wire causes the north pole of the compass needle to deflect towards the east, as per the right-hand thumb rule.

Question 28

An electron enters a magnetic field at right angles to it. According to Fleming's left-hand rule, what is the direction of the force acting on the electron?

Accepted Answer

Correct Option: D. Solution: Using Fleming's left-hand rule, the direction of the force is perpendicular to both the magnetic field and the direction of current (opposite to electron motion), resulting in a force directed into the page.

Question 29

An electron enters a magnetic field at right angles to its direction. Which of the following statements correctly describes the direction of the force acting on the electron?

Accepted Answer

Correct Option: C. Solution: According to Fleming's left-hand rule, the direction of the force on a negatively charged particle like an electron is opposite to that on a positive charge. Since the current direction is opposite to the electron flow, the force is directed into the page.

Question 30

Why do no two magnetic field lines intersect each other?

Accepted Answer

Correct Option: B. Solution: Magnetic field lines do not intersect because if they did, it would imply that the compass needle points in two directions at the point of intersection, which is impossible.

Question 31

A straight copper wire carrying a current is placed horizontally in a magnetic field directed vertically upwards. What will happen to the wire if the current is increased?

Accepted Answer

Correct Option: A. Solution: When the current in the wire is increased, the force experienced by the wire also increases according to the formula $F = BIL \sin 	heta$. Since the magnetic field is directed upwards and the current is along the wire, the force is perpendicular to both, causing the wire to move to the left.

Question 32

An electric oven of 2 kW power rating is operated in a domestic electric circuit (220 V) that has a current rating of 5 A. What result do you expect?

Accepted Answer

Correct Option: C. Solution: The power rating of the oven is 2 kW, which means it requires $$\frac{2000}{220} \approx 9.09$$ A. Since the circuit has a current rating of only 5 A, operating the oven will cause the circuit to overload, blowing the fuse.

Question 33

Consider a current-carrying solenoid. If a soft iron core is inserted into the solenoid, which of the following outcomes is expected?

Accepted Answer

Correct Option: C. Solution: Inserting a soft iron core into a solenoid increases the magnetic field strength inside the solenoid significantly, as the core becomes magnetized and enhances the magnetic field.

Question 34

A solenoid is carrying a current. Which statement correctly describes the magnetic field inside the solenoid?

Accepted Answer

Correct Option: D. Solution: The magnetic field inside a solenoid is uniform, as indicated by the parallel straight lines of the field inside the solenoid.

Question 35

Consider a circular loop of wire lying in the plane of the table with current passing through it clockwise. What is the direction of the magnetic field at the center of the loop?

Accepted Answer

Correct Option: B. Solution: Applying the right-hand rule, the fingers curl in the direction of the current, and the thumb points in the direction of the magnetic field. For a clockwise current, the field at the center is downwards.

Question 36

An electromagnet is formed by using a solenoid with a soft iron core. Which of the following statements is true about the magnetic field inside the solenoid?

Accepted Answer

Correct Option: C. Solution: The magnetic field inside a solenoid is uniform and resembles that of a bar magnet, with field lines running parallel and evenly spaced, indicating a uniform field.

Question 37

If a current-carrying conductor is placed in a magnetic field, when is the force on it the largest?

Accepted Answer

Correct Option: B. Solution: The force on a current-carrying conductor is largest when the current is at right angles to the magnetic field.

Question 38

Which of the following statements correctly describes the behavior of magnetic field lines around a bar magnet?

Accepted Answer

Correct Option: C. Solution: Magnetic field lines around a bar magnet form closed loops, emerging from the north pole and merging at the south pole outside the magnet.

Question 39

A current-carrying conductor is placed in a magnetic field, and it experiences a force. If the direction of the current is reversed, what happens to the direction of the force?

Accepted Answer

Correct Option: C. Solution: According to Fleming's left-hand rule, reversing the direction of current in a conductor will reverse the direction of the force experienced by it in a magnetic field.

Question 40

In an experiment, a current-carrying wire is placed perpendicular to a magnetic field. If the current in the wire is increased, what will be the effect on the force experienced by the wire?

Accepted Answer

Correct Option: C. Solution: The force experienced by a current-carrying conductor in a magnetic field is directly proportional to the current. Therefore, increasing the current will increase the force.

Question 41

According to Fleming's left-hand rule, if the forefinger points in the direction of the magnetic field and the second finger in the direction of current, what does the thumb represent?

Accepted Answer

Correct Option: B. Solution: According to Fleming's left-hand rule, the thumb represents the direction of force or motion on the conductor.

Question 42

An alpha-particle is projected towards the west and is deflected towards the north by a magnetic field. What is the direction of the magnetic field?

Accepted Answer

Correct Option: D. Solution: Using the right-hand rule for a positive charge, if the particle is deflected north when moving west, the magnetic field must be directed upward.

Question 43

What happens to the force on a current-carrying conductor when the direction of the current is reversed?

Accepted Answer

Correct Option: C. Solution: Reversing the direction of current through the conductor reverses the direction of the force acting on it.

Question 44

Magnetic field lines can intersect each other.

Accepted Answer

Answer: False. Solution: Magnetic field lines do not intersect each other because if they did, it would imply that the magnetic field has two different directions at the point of intersection, which is not possible.

Question 45

In a domestic electric circuit, the live wire is typically covered with red insulation.

Accepted Answer

Answer: True. Solution: The live wire in domestic circuits is usually covered with red insulation to distinguish it from the neutral and earth wires.

Question 46

The magnetic field lines around a current-carrying straight wire form concentric circles.

Accepted Answer

Answer: True. Solution: The magnetic field lines around a current-carrying straight wire form concentric circles centered on the wire, as determined by the right-hand thumb rule.

Question 47

An electromagnet is formed when a current-carrying solenoid is wrapped around a soft iron core, and it behaves similarly to a bar magnet.

Accepted Answer

Answer: True. Solution: An electromagnet consists of a coil of insulated copper wire wrapped around a core of soft iron, and it exhibits magnetic properties similar to a bar magnet when current flows through the solenoid.

Question 48

A compass needle gets deflected when placed near a current-carrying wire due to the magnetic field produced by the electric current.

Accepted Answer

Answer: True. Solution: The deflection of the compass needle indicates the presence of a magnetic field around the current-carrying wire, as observed in Oersted's experiment.

Question 49

The force on a current-carrying conductor in a magnetic field is maximum when the current is parallel to the magnetic field.

Accepted Answer

Answer: False. Solution: The force on a current-carrying conductor in a magnetic field is maximum when the current is perpendicular to the magnetic field, not parallel. This is because the magnetic force is given by $F = IBL \sin(	heta)$, where $	heta$ is the angle between the current and the magnetic field. The force is maximum when $	heta = 90^\circ$.

Question 50

The magnetic field lines around a current-carrying straight conductor form concentric circles.

Accepted Answer

Answer: True. Solution: The magnetic field lines around a current-carrying straight conductor are represented by concentric circles, as described in the text.

Question 51

In domestic electric circuits, the live wire is typically insulated with black color.

Accepted Answer

Answer: False. Solution: In domestic electric circuits, the live wire is usually insulated with red color, while the neutral wire is insulated with black color.

Question 52

Magnetic field lines are open curves that originate from the north pole and terminate at the south pole.

Accepted Answer

Answer: False. Solution: Magnetic field lines are closed curves. They emerge from the north pole and merge at the south pole outside the magnet, and inside the magnet, they move from the south pole to the north pole.

Question 53

A compass needle will not deflect when placed near a current-carrying wire.

Accepted Answer

Answer: False. Solution: A compass needle deflects when placed near a current-carrying wire due to the magnetic field produced by the electric current. This phenomenon was first observed by Hans Christian Oersted.

Question 54

A current-carrying conductor placed in a magnetic field experiences a force that is perpendicular to both the direction of the current and the magnetic field.

Accepted Answer

Answer: True. Solution: According to Fleming's left-hand rule, the force on a current-carrying conductor in a magnetic field is perpendicular to both the direction of the current and the magnetic field.

Question 55

The magnetic field lines around a straight current-carrying conductor are concentric circles.

Accepted Answer

Answer: True. Solution: The magnetic field lines around a straight current-carrying conductor form concentric circles, as demonstrated by the pattern of iron filings in experiments.

Question 56

The magnetic field inside a long straight solenoid carrying current is zero.

Accepted Answer

Answer: False. Solution: The magnetic field inside a long straight solenoid is uniform and non-zero, as indicated by the parallel straight lines of field inside the solenoid.

Question 57

The earth wire in a domestic electric circuit is used to provide a high-resistance path for current.

Accepted Answer

Answer: False. Solution: The earth wire provides a low-resistance path for current to ensure safety by preventing electric shock.

Question 58

The earth wire in a domestic circuit is used to prevent electric shocks by providing a low-resistance path for current leakage.

Accepted Answer

Answer: True. Solution: The earth wire is connected to the metallic body of appliances and provides a low-resistance path to the ground, ensuring any leakage current does not pose a risk of electric shock.

Question 59

The magnetic field inside a long straight solenoid carrying current is uniform.

Accepted Answer

Answer: True. Solution: The magnetic field inside a long straight solenoid carrying current is uniform, as indicated by the parallel straight lines of the field.

Question 60

The direction of the magnetic field produced by a current-carrying wire cannot be determined using the right-hand thumb rule.

Accepted Answer

Answer: False. Solution: The right-hand thumb rule is used to determine the direction of the magnetic field around a current-carrying conductor. By pointing the thumb in the direction of the current, the curl of the fingers shows the direction of the magnetic field lines.

Question 61

The magnetic field produced by a current-carrying circular loop is uniform at the center of the loop.

Accepted Answer

Answer: True. Solution: At the center of a current-carrying circular loop, the magnetic field lines are straight and uniform due to the symmetry of the loop.

Question 62

A current-carrying straight conductor generates a magnetic field consisting of concentric circles centered on the wire.

Accepted Answer

Answer: True. Solution: The magnetic field around a straight current-carrying conductor consists of concentric circles centered on the wire, as described by the right-hand thumb rule.

Question 63

The force on a current-carrying conductor in a magnetic field is zero if the current is parallel to the magnetic field.

Accepted Answer

Answer: True. Solution: The force experienced by a current-carrying conductor in a magnetic field is maximum when the current is perpendicular to the magnetic field and zero when the current is parallel to the magnetic field.

Question 64

The direction of the magnetic field produced by a current-carrying conductor can be determined using Fleming's left-hand rule.

Accepted Answer

Answer: False. Solution: Fleming's left-hand rule is used to determine the direction of force on a current-carrying conductor in a magnetic field, not the direction of the magnetic field itself. The right-hand thumb rule is used for determining the direction of the magnetic field.

Magnetic Effects of Elect..

Learning Objectives

Learning Objectives

Revision Notes & Summary

Chapter Notes

Magnetic Field due to Electric Current

Magnetic Field Lines

Force on a Current-Carrying Conductor

Electromagnetism in Circular Loops and Solenoids

Domestic Electric Circuits

Compass Needle and Magnetic Effect of Current

Electromagnet and Its Use

Exam Tips & Common Mistakes

Common Mistakes & Exam Tips

Magnetic Field due to Electric Current

Magnetic Field Lines

Force on a Current-Carrying Conductor

Electromagnetism in Circular Loops and Solenoids

Domestic Electric Circuits

Compass Needle and Magnetic Effect of Current

Electromagnet and Its Use

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Multiple Choice Questions

Q1.In a domestic electric circuit, what is the purpose of the earth wire?

Correct Answer: C

Q2.What happens to the direction of the compass needle when the direction of current in a nearby wire is reversed?

Correct Answer: B

Q3.A current-carrying conductor is placed in a magnetic field directed upwards. If the current flows from end B to end A of the conductor, in which direction will the conductor be displaced?

Correct Answer: A

Q4.A current-carrying straight conductor is placed vertically. If the current flows upwards, what is the direction of the magnetic field at a point directly east of the conductor?

Correct Answer: B

Q5.What happens when the live wire and neutral wire come into direct contact in a domestic circuit?

Correct Answer: C

Q6.Why don't two magnetic field lines intersect each other?

Correct Answer: B

Q7.A circular loop of wire is placed in the plane of the table and a current is passed through it in a clockwise direction. Using the right-hand rule, what is the direction of the magnetic field inside the loop?

Correct Answer: B

Q8.What happens to the deflection of a compass needle when the current in a nearby copper wire is increased?

Correct Answer: C

Q9.What happens to the current in a domestic circuit during a short circuit?

Correct Answer: C

Q10.In a domestic electric circuit, what is the function of the earth wire?

Correct Answer: C

Q11.According to Oersted's observation, what is the relationship between electricity and magnetism?

Correct Answer: B

Q12.Which rule helps determine the direction of the magnetic field around a current-carrying conductor?

Correct Answer: B

Q13.What happens to the direction of the magnetic field when the direction of current through a straight wire is reversed?

Correct Answer: B

Q14.Which rule is used to determine the direction of force on a current-carrying conductor in a magnetic field?

Correct Answer: B

Q15.A current-carrying conductor is placed in a magnetic field such that the direction of the current is perpendicular to the direction of the magnetic field. According to Fleming's left-hand rule, what is the direction of the force acting on the conductor?

Correct Answer: B

Q16.A positively-charged particle projected towards the west is deflected towards the north by a magnetic field. What is the direction of the magnetic field?

Correct Answer: D

Q17.According to the right-hand thumb rule, if the current flows upwards through a vertical conductor, in which direction do the magnetic field lines circulate?

Correct Answer: B

Q18.What happens to the magnetic field strength when the current through a straight conductor is increased?

Correct Answer: C

Q19.Which of the following correctly describes the magnetic field near a long straight wire?

Correct Answer: D

Q20.According to the right-hand thumb rule, if the thumb points in the direction of current, what do the fingers represent?

Correct Answer: B

Q21.A circular coil with multiple turns is placed in a uniform magnetic field. How does the magnetic field strength inside the coil compare to that of a single loop?

Correct Answer: C

Q22.How does the magnetic field inside a long straight solenoid-carrying current behave?

Correct Answer: D

Q23.Which wire in a domestic circuit is typically insulated with red color?

Correct Answer: B

Q24.In the context of magnetic field lines, what does the closeness of the lines indicate?

Correct Answer: A

Q25.What is the pattern of the magnetic field lines inside a long straight solenoid carrying current?

Correct Answer: D

Q26.What is the primary function of a solenoid when a current passes through it?