NCERT Solutions Class 10 Science Chapter 13

NCERT Solutions Class 10 Science Chapter 13 – Magnetic Effects of Electric Current

NCERT Solutions Class 10 Science Chapter 13 is about the Magnetic Effects of Electric Currents. This chapter is one of the crucial chapters, and it carries a weightage of ten marks in the examination. Students will learn about electric current, magnetic fields, magnetic field lines, compass, electromagnetic induction, effects of electric current, etc. Board exams regularly pick five marks questions on Oersted’s law and his experiment. .

Extramarks is one of the leading online learning platforms for Science and Mathematics from Classes 1 to 12. Our academic research team has prepared the study materials based on the latest CBSE syllabus and as per the NCERT guidelines. Students can confidently rely on our learning solutions for their class assignments, tests and exam preparation.

NCERT Solutions Class 10 Science Chapter 13 provided by Extramarks will help students understand the concepts clearly about the chapter Magnetic Effects of Electric Current. Our NCERT solutions provide chapter-specific information containing chapter notes, important questions with solved answers, revision notes, past question papers, etc. NCERT Solutions always strive to impart experiential and steer away from rote learning by providing step-by-step explanations for making the concepts easy for students and even clarify their doubts via live classes. Students who have registered with Extramarks NCERT Solutions have shown significant improvement in their academic results. No wonder students have complete trust and faith in Extramarks. .

Key Topics Covered In NCERT Solutions Class 10 Science Chapter 13

Class 10 Science Chapter 13 NCERT Solutions is about the Magnetic Effects of Electric Current. When electrically charged particles in the conductor, such as electrons, come into motion, they generate a magnetic field. This phenomenon is called the electromagnetic effect or magnetic effect of electric current. A detailed study of the Magnetic Effects of Electric Current is given below.

For every concept included in our Class 10 Science NCERT Solutions Chapter 13, an explanatory note is prepared by Extramarks Science subject matter experts who give step-by-step explanations for making the concepts easy for students and even clarify their doubts via live classes.

Magnetic Effects Of Electric Current
As detailed in the Class 10 Science Chapter 13 NCERT Solutions, Electric current has two effects:

Heating effect
Magnetic effect

We have already learned about the heating effect of electric current in the ‘Electricity’ chapter. Electric current also generates a magnetic effect. A magnetic field is a force field generated by moving electric charges and magnetic dipoles, applied to other close-by moving charges and magnetic dipoles. A compass needle deflection activity illustrates the magnetic effects of current flowing in a wire.

Step 1: Place a straight copper wire perpendicular to the plane of paper between the points X and Y in an electric circuit,

Step 2. Take a small compass and place it horizontally near this copper wire. Check the position of the needle.

Step 3. Run the current through the electric circuit by inserting the key into the plug.

Step 4. Examine the change in the position of the compass needle.

Students can carry this experiment at their home by following the steps as given in our NCERT Solutions Class 10 Science Chapter 13.

Magnetic Field and Field Lines
A magnetic field is a region surrounding a magnet or a moving electric charge in which magnetism is felt. The magnetic field is a tool to describe how the magnetic force is distributed in the space around and within something magnetic in nature.

Symbol
B or H
Unit
Tesla
Base Unit
(Newton. Second)/Coulomb

Demonstration of Magnetic Field

The magnetic field can be demonstrated in two different ways as below:

Magnetic Field Vector:

Magnetic Field Vector is the mathematical description of the magnetic field.

A vector field is a group of many vectors drawn on a grid.

In the case of a compass, the vector points in the direction of a compass.

The length of the vector depends on the strength of the magnetic force.

 

Magnetic Field Lines: Magnetic field lines indicate the direction of the magnetic force on a north monopole at any given point.

The solidity of the field lines indicates the magnitude of the field.

The magnetic field is more substantial and crowded near the magnetic poles.

Moving away from the bars weakens the magnetic field, making the lines less crowded.

The other properties include, magnetic field lines never crossing each other.

Magnetic field lines always make closed-loops.

Magnetic field lines always start from the north pole and end at the south pole.

The picture below shows the magnetic field lines:

 

The concept of magnetic field lines and magnetic field vectors is thoroughly explained with the help of visual diagrams and detailed explanations for students which help in shaping their minds to absorb more complex topics in higher classes. Refer to our NCERT Solutions Class 10 Science Chapter 13 which is available on Extramarks’ website and take a moment to explore a repository of study materials available to supplement your learning.

Magnetic Field Intensity
Magnetic field intensity is represented as Vector H and defined as the ratio of the MMF needed to create a certain Flux Density (B) within a particular material per unit length of that material.

The formula is H = B/μ – M, where B is the magnetic flux density, M is the magnetisation, and μ is the magnetic permeability.

Magnetic Field Due To A Current-Carrying Conductor
As we know, a magnetic field is produced whenever an electrical charge is in motion. Take a conducting wire and connect it to a battery. With the increasing current in the wire, the magnetic field also increases. Moving away from the wire results in a decrease in the magnetic field. This phenomenon is important for students to understand and to feed their insatiable curiosity we recommend they refer to our NCERT Solutions Class 10 Science Chapter 13.

According to Ampere’s law, the equation gives the magnetic field at a distance r from a long current-carrying conductor I.
B=μ0I2πr

In the equation, μ0 is a particular constant known as the permeability of free space.
μ0 = 4π*10-7 T. m/A

Force On A Current-Carrying Conductor In A Magnetic Field
An electrically charged conductor produces a magnetic field around it. i.e. behaves like a magnet and exerts a force when placed in its magnetic field. Similarly, the magnetic field also exerts equal and opposite forces on the current-carrying conductor.

When two magnetic fields (the magnetic field produced by the current-carrying conductor and the magnetic field due to the nearby magnet) interact, attraction or repulsion can occur between them. This attraction and repulsion are based on the direction of the external magnetic field and the current in the conductor.

Suppose the direction of the flow of the magnetic field and the electric current are perpendicular to each other. The force acting on the conductor is vertical to both the current and magnetic field. A conductor is placed between a horseshoe magnet’s north and south poles with an upward magnetic field and is connected to the battery, as depicted in the sketch below. When electricity is passed through the conductor by switching on the plug key, the conductor moves away from the horseshoe magnet, indicating that the force from the magnet is acting on the conductor. Now, suppose the polarity of either battery or the horseshoe magnet is reversed, and the electric current is passed. In that case, the conductor will move towards the magnet, indicating that the force’s direction is reversed.

Fleming’s left-hand rule is beneficial in determining the direction of the force. The left hand is stretched so that the forefinger, the center finger, and the thumb are in perpendicular directions.

According to the rule, the forefinger and the center finger of a stretched left-hand point in the direction of the magnetic field and the electric current, respectively, while the thumb points in the direction of motion of force acting on the conductor.

 

Students will find a few questions in exams related to the application of Fleming’s left-hand rule. They can find more real-life applications and use cases in our NCERT Solutions Class 10 Science Chapter 13.

Electric Motor
An electric motor is a revolving device that converts electrical energy to mechanical energy.

A simple electric motor consists of the following parts:

A power supply: Usually has DC for a simple motor. Provides power to the motor armature or field coils.

Field Magnet: Produces a torque on the armature coil under Fleming’s left-hand rule.

An Armature or rotor Holds the armature coil in place and provides mechanical support.

Commutator: It is the rotating interface of the armature coil with a stationary circuit.

Brushes: These devices conduct current between static wires and moving parts, most commonly the rotating shaft.

Working Principle of An Electric Motor:

The working of an electric motor depends on the fact that an electrically charged conductor produces a magnetic field around it.

For example:
Take two magnetic bars and keep the poles facing each other in a small space. Take a small length of an electric wire and make a loop. Place this loop in between the bar magnets such that it is still within the field of impact of the magnets. In the end, link the ends of the loop to a battery. Once electricity flows through the circuit, the magnetic field of the magnets interferes and, in turn, makes the loop move. As the loop has become a magnet now, one of the sides will be attracted to the north pole and the other to the magnet’s south pole.

 

Types of Electric Motor:

Electric motors are available in three main divisions:

AC motor.

DC motor.

Special purpose motors.

Image Source: NCERT Textbook

Uses of an Electric Motor:

Electric motors are used in numerous applications. Some of them are listed below:

1. Drills.

2. Water Pumps.

3. Hard Disc Drives.

4. Washing Machines.

5. Industrial Equipment.

Electric motors, their working, their applications and different types of motors are further discussed at length in our NCERT Solutions Class 10 Science Chapter 13. Students can sign up at Extramarks’ website and get full access to these study resources.

Electromagnetic Induction
Electromagnetic induction is the current produced because of voltage production due to a changing magnetic field around a fixed conductor or conductor moving inside a magnetic field.
English physicist Michael Faraday first discovered this in 1831.

Some of the discoveries of the factors influencing voltage production are:

1. Number of Coils:

The produced voltage is directly proportional to the wire coils. The greater the number of turns, the greater the voltage produced.

2. Changing Magnetic Field:

Changing the magnetic field affects the induced voltage.

Electromagnetic Induction Formula is e = N × dΦ / dt

Where e is the induced voltage (in volts), N is the number of turns in the coil, Φ is the magnetic flux – the amount of magnetic field at a surface (in Webbers), and t is the time (in seconds).

Applications of Electromagnetic Induction:

1. AC generators function on the principle of electromagnetic induction.

2. The working of electrical transformers is based on electromagnetic induction.

3. The magnetic flow metre is based on electromagnetic induction.

Electric Generator
As explained in our NCERT Solutions Class 10 Science Chapter 13, the electric generator is the electric machine that converts mechanical energy into electrical energy. Generators do not produce electricity; instead, it uses the mechanical energy supplied to them to force the movement of electric charges present in the wire of its windings through an external electric circuit. This flow of electrons constitutes the output electric current supplied by the generator.

Types of Electric Generators:

1. AC generators:

AC generators are single-phase generators and are limited to 25 kW.

2. DC generators:

These generators are divided into three categories:

Shunt: Shunt generators are used in battery chargers.

Series: Series generators are used in street lights.

Compound-wound: Most of the DC generators are compound-wound.

Uses of an Electric Generator:

1. They supply the power for most power networks across cities.

2. Small-scale generators provide a good backup for household power needs or small businesses.

3. At construction sites, before the power is set up, they extensively use electric generators.

4. Energy-efficient, as fuel consumption is reduced drastically.

5. Since they give a voltage output range, they are used in labs.

6. They are used to drive motors.

7. They are used in transportation.

There are many other uses and applications of electric generators that we have covered in our NCERT Solutions Class 10 Science Chapter 13.

Domestic Electric Circuits
The two types of Electric circuits are:

Parallel circuit.

Series circuit.

Electrons in the parallel circuit flow in many directions. Different branches connect individual parts of the circuit. If a circuit breaks in one direction, electric current flows in another direction.

In the series circuit, electrons flow in a single direction. Circuits can be opened or closed at one time. If the circuit breaks, no current flows in the circuit.

Electricity to homes is supplied through two types of cables:

Overhead cables.

Underground cables.

Three types of wires in domestic electric circuits are Earth wire(green colour), Live wire(red colour), and Neutral wire(black colour).

 

NCERT Solutions Class 10 Science Chapter 13: Exercises & Solutions

NCERT Solutions Class 10 Science Chapter 13 -Magnetic Effects of Electric Current, provided by Extramarks, covers all essential topics from the examination point of view. The solutions are prepared by experienced subject matter experts after a lot of research and analysis to provide authentic and reliable study material to students. Students can study chapter theories and also attempt various questions such as MCQs, short and long answer questions from our NCERT solutions. Students may refer to a repository of questions in NCERT Solutions Class 10 Science Chapter 13 – Magnetic Effects of Electric Current by clicking below.

NCERT Solutions – Short-answer Questions
NCERT Solutions – MCQ’s
NCERT Solutions – Long-answer Questions

As mentioned earlier Extramarks has plenty of study resources from Classes 1 to 12. Students may access NCERT Solutions for any class and subject by clicking on the respective links below:

NCERT SOLUTIONS FOR CLASS 10 SCIENCE
Chapter 1 Chemical Reactions and Equations
Chapter 2 Acids, Bases and Salts
Chapter 3 Metals and Non-metals
Chapter 4 Carbon and Its Compounds
Chapter 5 Periodic Classification of Elements
Chapter 6 Life Processes
Chapter 7 Control and Coordination
Chapter 8 How do Organisms Reproduce?
Chapter 9 Heredity and Evolution
Chapter 10 Light Reflection and Refraction
Chapter 11 Human Eye and Colourful World
Chapter 12 Electricity
Chapter 13 Magnetic Effects of Electric Current
Chapter 14 Sources of Energy
Chapter 15 Our Environment
Chapter 16

NCERT Exemplar Class 10 Science

NCERT Exemplar Class 10 Science Chapter 13 is one of the most acceptable studies and practice materials developed by experienced faculty. . In Science, it’s very important for students to understand the concepts and fundamentals of each topic. Once the fundamental concepts are clearly understood it becomes easy to understand these topics in higher classes. Students need to get acquainted with all types of questions to score good marks. By practising these advanced-level questions thoroughly, students get a good knowledge of all the concepts of this chapter, analyze their limitations and overcome them before facing the board examinations, and prepare well for competitive examination such as NEET, JEE, and other technical exams.
Furthermore, students can refer to the Exemplar problem and Solutions for Class 10 Science Chapter wise on the Extramarks’ website to master the topic and continue the process of learning with excellent academic results.

NCERT Solutions Class 10 Science -Exemplar Questions and Answers

Key Features of NCERT Solutions Class 10 Science Chapter 13
Extramarks platform is known for providing the most accurate and high-quality educational materials for all Classes from 1 to 12. . We have an in-house research and development team which meticulously follows the NCERT textbooks and CBSE guidelines to provide authentic and reliable study resources for students.. Today lakhs of students have complete faith and trust on Extramarks for their tests, assignments and exams.

The Benefits of NCERT Solutions Class 10 Science Chapter 13 include:

Includes all concepts from the CBSE syllabus and is based on the most recent NCERT 2021-22 pattern.
The answers present extensive and pertinent information clearly and concisely.
It assists students in reinforcing their fundamentals, making it easier for them to comprehend more complicated and difficult concepts. .
Time management, problem-solving, and analytical skills all can be developed by students.
NCERT Solutions, Extra questions help students to get a better hold on the subject. It helps them to solve any tricky questions with ease and fetch more marks in the examinations.
NCERT Solutions Class 10 Science Chapter 13 provides well-explained solutions to all the in-text and end-text questions in the textbook. Every student registered with Extramarks can access various study materials on all subjects and boost their performance.
The tough questions in between chapters encourage students to think outside the box to be able to apply the concepts acquired in the chapter in real life. Extramarks doesn’t believe in rote learning, in fact, it follows the latest CBSE guidelines to provide experiential learning to students

Q.1 Which of the following correctly describes the magnetic field near a long straight wire?

(a) The field consists of straight lines perpendicular to the wire.
(b) The field consists of straight lines parallel to the wire.
(c) The field consists of radial lines originating from the wire.
(d) The field consists of concentric circles centred on the wire.

Ans-

The correct option is (d).
Explanation: The magnetic field lines around a straight current-carrying conductor are concentric circles and the centres of these circles lie on the wire.

Q.2 The phenomenon of electromagnetic induction is

(a) the process of charging a body.
(b) the process of generating magnetic field due to a current passing through a coil.
(c) producing induced current in a coil due to relative motion between a magnet and the coil.
(d) the process of rotating a coil of an electric motor.

Ans-

The correct option is (c).
Explanation: A current is induced in the coil when a coil and a magnet are moved relative to each other. This phenomenon is called electromagnetic induction.

Q.3 The device used for producing electric current is called a

(a) generator.
(b) galvanometer.
(c) ammeter.
(d) motor.

Ans-

The correct option is (a).
Explanation: Electric current is generated by an electric generator. An electric generator converts mechanical energy into electric energy.

Q.4 The essential difference between an AC generator and a DC generator is that

(a) AC generator has an electromagnet while a DC generator has permanent magnet.
(b) DC generator will generate a higher voltage.
(c) AC generator will generate a higher voltage.
(d) AC generator has slip rings while the DC generator has a commutator.

Ans-

The correct option is (d).
Explanation: The main difference between AC generator and DC generator is that an AC generator has two rings known as slip rings while a DC generator has two half rings known as commutator.

Q.5 At the time of short circuit, the current in the circuit
(a) reduces substantially.
(b) does not change.
(c) increases heavily.
(d) vary continuously.

Ans-

The correct option is (c).

Explanation: In the case of short-circuit, the resistance of the circuit becomes zero. Hence, the magnitude of the current flowing through the circuit increases quickly.

Q.6 State whether the following statements are true or false.

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

Ans-

(a) False
Explanation: An electric motor converts electrical energy into mechanical energy.

(b) True
Explanation: An electric generator produces electricity by rotating a coil in presence of a magnetic field. It works on the principle of electromagnetic induction.

(c) True
Explanation: A long circular coil behaves like a long solenoid. The magnetic field lines inside the solenoid are parallel to each other.

(d) False
Explanation: Earth wire has green insulation colour while live wire has red insulation cover.

Q.7 List two methods of producing magnetic fields.

Ans-

Two methods for producing magnetic field are as follows:

(a) By using permanent magnets.
(b) By using a current carrying conductor.

Q.8 How does a solenoid behave like a magnet? Can you determine the north and south poles of a current–carrying solenoid with the help of a bar magnet? Explain.

Ans-

Solenoid: It is a long coil of circular loops of insulated copper wire. When electric current is passed through it, the magnetic field lines are produced around it. The magnetic field produced by a solenoid is similar to the magnetic field of a bar magnet.

When the north pole of a bar magnet is brought near the end connected to the negative terminal of the battery, the solenoid repels the bar magnet. Since like poles repel each other, the end connected to the negative terminal of the battery behaves like the north pole of the solenoid and the other end behaves like a south pole. Therefore, one end of the solenoid behaves as a north pole and the other end behaves as a south pole.

Q.9 When is the force experienced by a current–carrying conductor placed in a magnetic field largest?

Ans-

When the direction of electric current is perpendicular to the direction of the magnetic field, the force experienced by a current-carrying conductor is maximum.

Q.10 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 magnetic field?

Ans-

The direction of magnetic field can be found with the help of Fleming’s left hand rule. The direction of magnetic field inside the chamber would be perpendicular to the direction of current and direction of force and it would be either upward or downward. As the negatively charged electrons are moving from back wall to the front wall hence, the direction of current would be from the front wall to the back wall. The direction of magnetic force is rightward. Therefore, according to Fleming’s left hand rule, the direction of magnetic field inside the chamber would be downward.

Q.11 Draw a labelled diagram of an electric motor. Explain its principle and working. What is the function of a split ring in an electric motor?

Ans-

An electric motor is a device which converts electrical energy into mechanical energy. It is based on the principle that current carrying conductor experiences a force, when placed in a magnetic field.

When a current is allowed to flow through the coil ABCD by closing the key, the coil starts rotating anti-clockwise. It is because a downward force acts on length AB and at the same time, an upward force acts on length CD. Thus, the coil rotates anti-clockwise. Current in the length AB flows from A to B and the magnetic field acts from left to right, normal to length AB. Hence, according to Fleming’s left hand rule, a downward force acts on the length AB. Similarly, current in the length CD flows from C to D and the magnetic field acts from left to right, normal to the flow of current. Therefore, an upward force acts on the length CD. These two forces cause the coil to rotate anti-clockwise. After half a rotation, the position of AB and CD interchanges. The half-ring P comes in contact with brush X and half-ring Q comes in contact with brush Y. Hence, the direction of current in the coil ABCD gets reversed. The current flows through the coil in the direction DCBA. The reversal of current through the coil ABCD repeats after each half rotation. As a result, the coil rotates unidirectional. The split rings help to reverse the direction of current in the circuit. These rings are called as commutator.

Q.12 Name some devices in which electric motors are used.

Ans-

The devices in which electric motors are used are washing machines, water pumps, electric fans and electric mixers.

Q.13 A coil of insulated copper wire is connected to a galvanometer. What will happen if a bar magnet is (i) pushed into the coil, (ii) withdrawn from inside the coil, (iii) held stationary inside the coil?

Ans-

A current is induced in a solenoid when a bar magnet is moved relative to it. This is the principle of electromagnetic induction.

(i) When a bar magnet is pushed into a coil, a current is induced for a moment. Therefore, the needle of the galvanometer deflects for a short time in a particular direction.

(ii) When the bar magnet is moved away from the coil, a current is again induced for a moment in opposite direction. Thus, the needle of the galvanometer deflects for a short time in the opposite direction.

(iii) When a bar magnet remains stationary inside the coil, no current will be induced in the coil. Therefore, galvanometer will show no deflection.

Q.14 Two circular coils A and B are placed closed to each other. If the current in the coil A is changed, will some current be induced in the coil B? Give reason.

Ans-

On changing the magnitude of electric current in coil A, the magnetic field linked with it also changes and hence, the magnetic field around coil B also changes. Due to this, an electric current induces in coil B. This effect is called electromagnetic induction.

Q.15 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.

Ans-

(i) Maxwell’s right hand thumb rule is used to find the direction of magnetic field produced around a straight conductor carrying current.

(ii) Fleming’s left hand rule is used to find the direction of force experienced by a current carrying straight conductor placed in a magnetic field which is perpendicular to it

(iii) Fleming’s right hand rule is used to find the direction of current induced in a coil due to its rotation in a magnetic field.

Q.16 Explain the underlying principle and working of an electric generator by drawing a labelled diagram. What is the function of brushes?

Ans-

It is an electrical device which converts mechanical energy into electrical energy.
Principle: When a loop is moved in a magnetic field, an electric current is induced in the coil. An electric generator produces electricity by rotating a coil in a magnetic field.

Working: It consists of a coil ABCD which is mounted on a rotor shaft. The coil’s axis of rotation is placed perpendicular to the magnetic field (N-S). The two other ends of the armature are connected separately to two split rings P and Q. The split rings are then connected to two conducting carbon brushes X and Y. A galvanometer G is connected with external circuit.

If the coil ABCD is rotated clockwise, then the length AB moves upwards while length CD moves downwards. Since the lengths AB and CD are moving in a magnetic field, a current will be induced in both of them due to electromagnetic induction. Length AB is moving upwards and the magnetic field acts from left to right. Hence, according to Fleming’s right hand rule, the direction of induced current will be from A to B. Similarly, the direction of induced current in the length CD will be from C to D.

The direction of current in the coil is ABCD. Thus, the galvanometer shows a deflection in a particular direction. After half a rotation, length AB starts moving down whereas length CD starts moving upward. The direction of the induced current in the coil gets reversed as DCBA. As the direction of current gets reversed after each half rotation, the produced current is called an alternating current.

In the case of DC generator, instead of slip rings, two split rings are used. In this arrangement, brush X always remains in contact with the length of the coil that is moving up whereas brush Y always remains in contact with the length that is moving down. The split rings P and Q act as a commutator.

The direction of current induced in the coil will be ABCD for the first rotation and DCBA in the second half of the rotation. Hence, a unidirectional current is produced in a DC generator.

Q.17 When does an electric short circuit occur?

Ans-

When the resistance of an electric circuit becomes very low, the magnitude of electric current flowing through the circuit becomes very high. This happens when many appliances are connected to a single socket and thus, results short-circuiting. Moreover, when a live wire touches neutral wire directly, the current flowing in the circuit increases suddenly. Thus, a short circuit occurs.

Q.18 What is the function of an earth wire? Why is it necessary to earth metallic appliances?

Ans-

An earth wire joins a metallic body of an electric appliance to the earth so that any leakage of electric current is transferred to the ground. This avoids any electric shock to the user. Thus, earthing of the electrical appliances is very important.

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FAQs (Frequently Asked Questions)

Extramarks NCERT Solutions Class 10 Science Chapter 13 is prepared by subject matter experts with years of experience. Our solution explains the concepts of magnetic effects well with various diagrams and answers all the questions present in the textbook. While writing answers, students follow specific guidelines. For this, read through solutions, and learn how to answer questions without making careless slips.Hence it becomes easier for students to score well in examination.

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