Magnetic Effect of Electric Current Class 10 NCERT Solutions

NCERT Solutions for Class 10 Science Chapter 12, Magnetic Effects of Electric Current, help students understand how current produces magnetic fields and how these fields interact with conductors and magnets.

The chapter explains concepts like magnetic fields around a current-carrying conductor, electromagnets, and applications in devices such as electric motors and galvanometers.

Using these Magnetic Effect of Electric Current Class 10 solutions, students can grasp complex concepts easily, practice questions, and prepare effectively for exams following the CBSE Class 10 Science syllabus.

Magnetic Effects of Electric Current Class 10 NCERT Solutions

Magnetic Effect of Electric Current Class 10 Questions and Answers​

 NCERT Solutions of Magnetic Effect of Electric Current Class 10 Questions and Answers provide clear explanations of key concepts like magnetic fields, electromagnets, and forces on current-carrying conductors. These solutions help students practice effectively and score well in exams.

1. Why does a compass needle get deflected when brought near a bar magnet?

Solution:

When a compass needle is brought near a bar magnet, it gets deflected due to the interaction between the magnetic fields. The compass needle itself is a small magnet with its own magnetic field. When it is close to the bar magnet, the magnetic field of the bar magnet exerts a force on the compass needle. This force causes the needle to align with the magnetic field of the bar magnet, leading to its deflection. The degree of deflection indicates the strength and direction of the magnetic field created by the bar magnet.

2. Draw magnetic field lines around a bar magnet.

Solution:

Magnetic field lines of a bar magnet always emerge from the North Pole and curve around to enter the South Pole. This pattern forms a closed loop around the magnet. When the compass needle is brought near the bar magnet, it aligns with these magnetic field lines, causing it to deflect. The direction and strength of the deflection provide information about the magnetic field's direction and intensity around the magnet.

3. List the properties of magnetic field lines.

Solution:

The properties of magnetic field lines are as follows:

• Magnetic field lines do not intersect each other; if they did, it would imply two different directions for the magnetic field at the point of intersection, which is not possible.
• Magnetic field lines emerge from the North Pole of a magnet and terminate at the South Pole, creating a continuous loop.
• Inside the magnet, the direction of the field lines is from the South Pole to the North Pole, completing the loop of the magnetic field.

4. Why don’t two magnetic field lines intersect each other?

Solution:

Two magnetic field lines do not intersect because if they did, it would imply that at the point of intersection, the compass needle would point in two different directions simultaneously. This is not possible as a magnetic field has only one direction at any given point. Thus, to maintain a consistent direction of the magnetic field, the field lines do not cross each other.

5. Consider a circular loop of wire lying in the plane of the table. Let the current pass through the loop clockwise. Apply the right-hand rule to find out the direction of the magnetic field inside and outside the loop.

Solution:

For a current flowing in a loop, the direction of the magnetic field depends on the direction of the current. If the current flows downward through the loop, the magnetic field will appear to emerge from the table surface outside the loop and merge with the table surface inside the loop. Conversely, if the current flows upward, the magnetic field will appear to emerge from the table surface inside the loop and merge with the table surface outside the loop. This directionality of the magnetic field follows the right-hand rule, which is used to determine the orientation of the magnetic field around a current-carrying loop.

6. The magnetic field in a given region is uniform. Draw a diagram to represent it.

Solution:

7. Choose the correct option.

The magnetic field inside a long straight solenoid carrying current

1. is zero.
2. decreases as we move towards its end.
3. increases as we move towards its end.
4. is the same at all points.

Solution:

d. is the same at all points

8. Which of the following properties of a proton can change while it moves freely in a magnetic field? (There may be more than one correct answer.)

1. Mass
2. Speed
3. Velocity
4. Momentum

Solution:

(c) and (d)

9. In Activity 13.7, how do we think the displacement of rod AB will be affected if (i) current in rod AB is increased; (ii) a stronger horse-shoe magnet is used; and (iii) length of the rod AB is increased?

Solution:

When a current-carrying conductor, such as rod AB, is placed in a magnetic field, it experiences a force due to the interaction between the current and the magnetic field. The magnitude of this force depends on several factors, and it will increase if:

• The current in rod AB is increased: The force experienced by the rod is directly proportional to the amount of current flowing through it. Hence, increasing the current will increase the magnetic force exerted on the rod.
• A stronger horseshoe magnet is used : The force is also directly proportional to the strength of the magnetic field. Using a stronger magnet will increase the strength of the magnetic field, thereby increasing the force on the rod.
• When the length of the rod AB increases : The force is directly proportional to the length of the conductor within the magnetic field. Therefore, increasing the length of the rod will increase the force exerted on it.

10. A positively-charged particle (alpha-particle) projected towards the west is deflected towards north by a magnetic field. The direction of magnetic field is

1. towards south
2. towards east
3. downward
4. upward

Solution:

The direction of the magnetic field can be determined using Fleming’s Left-hand Rule. According to this rule, if you arrange your thumb, forefinger, and middle finger of your left hand perpendicular to each other:

• The thumb points in the direction of the magnetic force.
• The forefinger points in the direction of the magnetic field.
• The middle finger points in the direction of the current.

Given that the direction of the positively charged particle is towards the west, this means the current is also directed towards the west. According to Fleming's Left-hand Rule, if the magnetic force is towards the north, the magnetic field must be directed upwards. This is because, with your left hand positioned such that the middle finger points west (current), the thumb points north (force), and the forefinger points upwards (magnetic field).

11. Name two safety measures commonly used in electric circuits and appliances.

Solution:

• Fuse: Each circuit should be connected to a fuse because it prevents the flow of excessive current. When the current exceeds the fuse's maximum limit, the fuse melts, stopping the current flow and protecting the connected appliance.
• Earthing: Earthing protects users from electric shocks. It transfers any leakage of current in an appliance to the ground, thereby preventing electric shocks and ensuring user safety.

12. 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? Explain.

Solution: The current drawn by the electric oven can be calculated using the formula P = V × I I = P/V Substituting the values, we get I = 2000 W/220 V = 9.09 A The current drawn by the electric oven is 9.09 A which exceeds the safe limit of the circuit. This causes the fuse to melt and break the circuit.

13. What precautions should be taken to avoid the overloading of domestic electric circuits?

Solution:

To avoid overloading domestic electric circuits, consider the following precautions:

• Avoid Connecting Too Many Devices to a Single Socket: Plugging multiple devices into one socket can overload the circuit and increase the risk of overheating and fires.
• Avoid Using Too Many Appliances Simultaneously: Operating many high-power appliances at the same time can exceed the circuit's capacity, leading to overloading and potential damage.
• Do Not Connect Faulty Appliances: Faulty or damaged appliances should not be plugged in, as they can cause short circuits and increase the risk of electrical hazards.

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

1. The field consists of straight lines perpendicular to the wire.
2. The field consists of straight lines parallel to the wire.
3. The field consists of radial lines originating from the wire.
4. The field consists of concentric circles centered on the wire.

Solution: 4. The field consists of concentric circles centred on the wire.

15. At the time of short circuit, the current in the circuit

1. reduces substantially.
2. does not change.
3. increases heavily.
4. vary continuously.

Solution: 3. increases heavily

16. State whether the following statements are true or false.

1. An electric motor converts mechanical energy into electrical energy.
2. An electric generator works on the principle of electromagnetic induction.
3. The field at the centre of a long circular coil carrying current will be parallel straight lines.
4. A wire with green insulation is usually the live wire of an electric supply.

Solution: 1. False 2. True 3. True 4. False

17. List two methods of producing magnetic fields.

Solution:

• Using a Permanent Magnet: A magnetic field can be produced by a permanent magnet. This field is visible by spreading iron filings on a white sheet of paper and placing the magnet underneath. The iron filings align along the magnetic field lines, showing the shape and direction of the field.
• Current-Carrying Straight Conductor: A magnetic field is generated around a straight conductor when an electric current passes through it. The direction and shape of the magnetic field can be observed using a compass or iron filings.
• Solenoids and Circular Loops: Different types of conductors, such as solenoids (coils of wire) and circular loops, can also produce magnetic fields. By passing current through these conductors, the resulting magnetic field can be visualized and measured, demonstrating how the field is concentrated within and around the coil or loop.

When the north pole of a bar magnet is brought close to the end of a solenoid connected to the negative terminal of a battery, the solenoid experiences a repulsive force. This repulsion occurs because like poles repel each other. From this observation, we can infer that the end of the solenoid connected to the negative terminal of the battery behaves as a north pole, while the end connected to the positive terminal acts as a south pole.

18. When is the force experienced by a current–carrying conductor placed in a magnetic field largest?

Solution: When the direction of the current is perpendicular to the direction of the magnetic field, the force experienced by the conductor is at its maximum.

19. Imagine that you are sitting in a chamber with your back to one wall. An electron beam, moving horizontally from back wall towards the front wall, is deflected by a strong magnetic field to your right side. What is the direction of the magnetic field?

Solution: The direction of the magnetic field can be determined using Fleming’s Left-Hand Rule. According to this rule, if we arrange our thumb, forefinger, and middle finger of the left hand perpendicular to each other, the thumb indicates the direction of the magnetic force, the middle finger shows the direction of the current, and the forefinger points in the direction of the magnetic field. In this case, the current flows from the front wall to the back wall of the chamber, which means negatively charged electrons move in the opposite direction, from the back wall to the front wall. Given that the magnetic force is directed rightward, and the direction of the current is perpendicular to this force, Fleming’s Left-Hand Rule reveals that the magnetic field direction inside the chamber is downward.

20. State the rule to determine the direction of a (i) magnetic field produced around a straight conductor-carrying current, (ii) force experienced by a current-carrying straight conductor placed in a magnetic field which is perpendicular to it, and (iii) current induced in a coil due to its rotation in a magnetic field.

Solution:
(i) The rule used to determine the direction of the magnetic field produced around a straight conductor carrying current is Maxwell’s right-hand thumb rule . According to this rule, if you point your thumb in the direction of the current, your curled fingers show the direction of the magnetic field lines around the conductor.
(ii) The rule used to determine the force experienced by a current-carrying straight conductor placed in a magnetic field that is perpendicular to it is Fleming’s left-hand rule. This rule helps to find the direction of the force acting on the conductor, where the thumb represents the force, the forefinger represents the magnetic field, and the middle finger represents the current.
(iii) The rule used to determine the current induced in a coil due to its rotation in a magnetic field is Fleming’s right-hand rule. This rule indicates the direction of the induced current when a conductor moves in a magnetic field, where the thumb points in the direction of the motion of the conductor, the forefinger in the direction of the magnetic field, and the middle finger shows the direction of the induced current.

21. What is the function of an earth wire? Why is it necessary to earth metallic appliances?

Solution: The metallic body of electric appliances is earthed using an earth wire to enhance safety. If there is any leakage of electricity from the appliance, the earth wire safely transfers this unwanted current to the ground. This grounding process prevents the user from receiving electric shocks, thus protecting against potential electrical hazards. Proper earthing is crucial for ensuring the safety of metallic appliances and reducing the risk of electrical accidents.

How Students Can Use Magnetic Effect of Electric Current Class 10 Solutions

Students can effectively use these NCERT Solutions to:

• Understand Concepts Clearly: Grasp topics like magnetic fields, force on a current-carrying conductor, and electromagnetic induction in a simple manner.

• Prepare as per Exam Pattern: Solutions are aligned with the Class 10 exam pattern, helping students focus on important questions.

• Practice Questions Efficiently: Solve all chapter questions, ensuring better conceptual clarity and exam readiness.

• Quick Revision: Use these solutions for last-minute revision to recall formulas, diagrams, and key concepts.

• Supplement Class 10 Notes: Acts as a reliable reference to reinforce notes and improve problem-solving skills.

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