# Class 10 Science Chapter 13 Magnetic Effects of Electric Current

Class 10 Science Chapter 13 Magnetic Effects of Electric Current The answer to each chapter is provided in the list so that you can easily browse throughout different chapters NCERT Class 10 Science Chapter 13 Magnetic Effects of Electric Current and select need one.

### Class 10 Science Chapter 13 Magnetic Effects of Electric Current

Also, you can read the SCERT book online in these sections Solutions by Expert Teachers as per SCERT (CBSE) Book guidelines. These solutions are part of SCERT All Subject Solutions. Here we have given Assam Board Class 10 Science Chapter 13 Magnetic Effects of Electric Current Solutions for All Subjects, You can practice these here…

Additional Questions and Answers

Q.1. Define magnet and magnetism.

Ans :- The substances which have the property of attracting small pieces of iron, nickle, cobalt etc are called magnets and this property of attraction is called magnetism.

Q.2. What is magnetic poles?

Ans :- The regions of concentrated magnetic strength inside the magnet just near its ends are called magnetic poles. The pole of freely suspended magnet which points towards north is called north pole and that points towards south is called south pole.

Q.3. What is the basis law of magnetic poles?

Ans :- It stalis that like pdes repel while unlike poles of 3. magnets attract each other.

Q.4. What are the basic properties of magnets?

Ans :- ( i ) Magnets attract small pieces of iron, nickes cobalt etc.

( ii )  When freely suspended, they come to rest in north-south direction.

( iii ) Like magnetic poles repel each other and unlike magnetic poles attract each other.

( iv ) The magnetic poles always exist in pairs.

Q.5. What is artificial magnet ?

Ans :- Pieces of iron and other magnetic materials which can be made to acquire the properties of natural magnets are called artificial magnets.

Q.6. What is magnetic field?

Ans :- It is the region around a magnet within which its influence can be experienced.

Q.7. Define magnetic line of force.

Ans :- It may be defined as the path in a magnetic field in which a unit north pole tends to move when allowed to do so. It may also be defined as a curve, the tangent to which at any point gives the direction of the magnetic field at that point.

Q.8. What is solenoid?

Ans :- Along cylindrical coil of insulated copper wire of large number of circular turns is called a solenoid.

Q.9. What ir direct current?

Ans :- It is thawt current which flows in a circuit with a constant magnitude in the same direction.

Q.10. What is alternating current?

Ans :- It is that current whose magnitude and direction change alternately and regularly with the passage of time.

Q.11. Name an instrument used determine the direction.

Ans :- Magnetic compass needle.

Q.12. What is an electric motor?

Ans :- It is a device to convert electric energy into mechanical energy.

Q.13. What is function of electric fuse?

Ans :- It is a safety device to save the houses from fire due to overloading or short circuit.

Q.14. What is colour code for different wires used in household?

Ans :- Live wires red, neutral is black and earth wire is green.

Q.15. What is frequency of A.C. supplied in India?

Ans :- 50HZ.

Q.16. Compare the permanent magnet and an electromagnet.

Ans :-

Q.17. What is the role of two conducting stationary brushes in sa a simple electric motor?

Ans :- Brushes touch the other side of two halves of the split ring and connect this to the battery. It maintains contact of rings with the battery.

Q.18. What is SI unit of magnetic flux?

Ans :- Webber (Wb)

Q.19. What should be the properties of a fuse wire?

Ans :- ( i ) It should be made of a material of low melting point.

( ii ) Specific resistance of material should be high.

Q.20. What is the principle of electric generator?

Ans :- Fleming’s right hand rule.

Q.21. What is compass needle?

Ans :- It is a small magnetic needle pivoted at the centre of a small circular brass case provided with a glass top. It is used to find the direction of magnetic field.

Q.22. How does the strength of the magnetic field at the centre of a circular coil of wire depend on

( i ) The radius of the coil.

( ii ) The number of turns of wire in the coil.

( iii ) The strength of current flowing in the coil?

Ans :- The magnetic field produced at the centre of circular coil carrying coil depends on following factors:-

( i ) It is inversely proportional to the radius of the coil. That is

B ∞ 1 / r

( ii ) It is directly proportional to the number of turns n of the coil. As the direction of current in each circular turn is same, the fields due to the various turns get added up. That is

B ∞ n

( iii ) It is directly proportional to the strength of current passing the coil. That is

B ∞ I

Q.23. Give some uses of permanent magnets.

Ans :- ( i ) In microphones, loudspeakers and electric clocks.

( ii ) In devices like ammeters, voltmeters and speedometers.

( iii ) In electric generators and motors.

( iv ) On video and audio cassette tapes.

Q.24. What is the meaning of the term ‘frequency’ of an alternating current? What is its value in India?

Ans :- The frequency of an alternating current is the number of times the direction of electric current change in one second. In India, the frequency of a.c. is 50 Hz.

Q.25. How can it be shown that a magnetic field exists around a wire through which a direct electric current is passing?

Ans :- A magnetic needle brought close to a straight current carrying wire aligns itself perpendicular to the wire, reversing the direction of current reverses the direction of deflection. This shows that the current carrying wire is associated with a magnetic field.

Q.26 How is an electromagnet different from a permanent magnet?

Ans :- An electromagnet loses its magnetism when the current through its solenoid is switched off. A permanent magnet retains magnetism for a long time.

Q.27. Why is essential to earth electrical appliances having metallic body?

Ans :- Earth wire is used as a safety measure to ensure that any leakage of current to the metallic body of an appliance does not give any severe shock to the user.

Q.28. Fill in the blanks :

( i ) A generator converts ————– into ————- energy.

( ii ) Electric switch is connected to ————- wire.

( iii ) At time of short circuit current in the circuit ————–.

( iv ) Commercial unit of electric energy is ————.

( v ) A long wound cylindrical coil of insulated wire is called ————- .

Ans :- ( i ) Mechanical; electric.

( ii ) Live.

( iii ) Increases heavily.

( iv ) kwh.

( v ) Solenoid.

Q.29. What is transformer?

Ans :- It is a device which converts low voltage at high current in to high voltage at low current and vice versa.

Q.30. What is Ampere’s swimming rule?

Ans :- Imagine a person swimming along the direction of the current, current entering the foot and leaving the head, the face turned towards the compass with hands spread normal to the body then the north pole will be deflected towards his left hand.

Multiples choice questions

Q.1. The magnetic lines of force

( a ) Always intersect each other.

( b ) Never intersect each other.

( c ) Sometimes intersect and sometimes do not intersect.

( d ) Are always parallel to each other.

Ans :- ( b ) Never intersect each other.

Q.2. The magnetic effect of current was discovered by

( a ) Faraday.

( b ) Henry.

( c ) Oersted.

( d ) Maxwell.

Ans :- ( c ) Oersted.

Q.3. When soft iron bar is introduced inside a current carrying solenoid, the magnetic field inside the solenoid coil.

( a ) Increase.

( b ) Decrease.

( c ) be zero.

( d ) Remain unaffected.

Ans :- ( a ) Increase.

Q.4. An electric motor transfers :

( a ) Electric energy into mechanical energy.

( b ) Mechanical energy into electric energy.

( c ) Chemical energy to electric energy.

( d ) Electric energy to sound energy.

Ans :- ( a ) Electric energy into mechanical energy.

Q.5. Material of the core of strong electromagnet is :

( a ) Soft iron.

( b ) Stell.

( d ) Laminated steel strips.

Ans :- ( d ) Laminated steel strips.

Q.6. The direction of induced current is given by

( a ) Ampere’s swimming rule.

( b ) Fleming’s left hand rule.

( c ) Fleming’s right hand rule.

( d ) Maxwell’s cork screw rule.

Ans :- ( c ) Fleming’s right-hand rule.

Q.7. An electric generator actually acts as

( a ) A source of electric charge.

( b ) A source of heat energy.

( c ) An electromagnet.

( d ) A converter of energy.

Ans :- ( d ) A converter of energy.

Q.8. The electric fuse and switches should be connected to

( a ) Live wire.

( b ) Neutral wire.

( c ) Earth wire.

( d ) None of these.

Ans :- ( a ) Live wire.

Q.9. The frequency of A.C. mains used in India is

( a ) 30 cpsu.

( b ) 50 cps.

( c ) 60 cps.

( d ) 120 cps.

Ans :- ( b ) 50 cps.

Q.10. The device based on the principle of electromagnetic induction is

( a ) Electric generator.

( b ) Electric motor.

( c ) Voltmeter.

( d ) Ammeter.

Ans :- ( a ) Electric generator.

Q.11. A positive charge projected toward east is deflected towards north by a magnetic field. The magnetic field is directed.

( a ) Towards west.

( b ) Towards south.

( c ) Upward.

( d ) Downward.

Ans :- ( d ) Downward.

Q.12. A bar magnet falls vertically through a magnet. Its acceleration is

( a ) Less thang g.

( b ) More than g.

( c ) Equal to g.

( d ) Zero.

Ans :- ( a ) Less thang g.

Q.13. The force on a charged particle is moving in a magnetic field is maximum when the angle between direction of motion and field is

( a ) Zero.

( b ) 90°

( c ) 180°

( d ) 45°

Ans :- ( b ) 90°

Q.14. Commercial electric motors do not use :

( a ) An electromagnet to rotate the armature.

( b ) Effectively large number of turns of conducting wire in the current carrying coil.

( c ) A permanent magnet to rotate the armature.

( d ) A soft iron core on which the coil is wound.

Ans :- ( c ) A permanent magnet to rotate the armature.

Q.15. The most important safely method used for protecting home appliances from short circuiting or overloading is :

( a ) Earthing.

( b )  Use of fuse.

( c ) Use of stabilizers.

( d ) Use of electric meter.

Ans :- ( b ) Use of fuse.

Q.16. What is electromagnet? How strength of an electromagnet can be increase?

Ans :- It is a solenoid with a soft iron core placed inside it. When current is passed through the solenoid the soft iron core becomes a temporary magnet. The strength of an electromagnet can be increased by

( i ) Increasing the number of turns per unit length of the coil.

( ii ) Increasing the strength of current and

( iii ) Winding the coil over a soft iron core.

Q.17. What do you mean by Earthing?

Ans :- Earthing of an electrical appliance means connecting the metallic body of the powered appliance to the earth through the earth wire. It is a safety measure which ensure any leakage of current to the metallic body of the appliance keeps its potential equal to that of the earth and the user may not get a severe electric shock.

Q.18. What is magnetic effect of current?

Ans :- A current carrying conductor produces a magnetic field around it. This effect is called magnetic effect of current.

Q.19. Write the importance of magnetism in medicine.

Ans :- An electric current always produces a magnetic field. Even weak ion currents that travel along the nerve cells in our body produce magnetic fields. When we touch something, our nerves carry an electric impulse to the muscles we need to use. This impulse produces a temporary magnetic field. These fields are very weak and are about one billion of the earth’s magnetic field. Two main organs in the human body where the magnetic field produced is significant are the heart and the brain.

The magnetic field inside the body forms the basis of obtaining the images of different body parts. This is done using a technique called Magnetic resonance Imaging. Analysis of these images helps in medical diagnosis. Magnetism has, thus, got important uses in medicine.

Q.20. What is galvanometer?

Ans :- A galvanometer is an instrument that can detect the presence of a current in a circuit. The pointer remains at zero for zero current flowing through it. It can deflect either to the left or the right of the zero mark depending on the direction of current.

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