Magnetic Effects Of Current, Class 10th Notes

THESE NOTES ARE PREPARED ACCORDING TO JKBOSE SYLLABI IN SIMPLIFIED AND CONCISE PATTERN

Unit Summary:

Magnetic Effect of Current	First Discovered by Hans Christian Oestered
Magnetic field   near a Bar Magnet	In form of Closed curved lines, Direction: North to South
Magnetic field near a current     carrying conductor	In form of Concentric circles, Direction given by Right hand thumb rule
SNOW rule	Used to know direction in which compass needle moves when placed near a current carrying conductor
Magnetic field near a Solenoid	In form of closed curved lines, Direction: Noth to South outside, and South to North inside a Solenoid.
Electric Motor	Converts electric energy into mechanical energy.
Amperes experiment	Helped to demonstrate that current carrying conductor experiences force in a magnetic field
Electric Generator	Converts Mechanical energy into Electric energy
Electromagnetic Induction	Production of current in circuit due to change in magnetic field. Discovered by Michael Faraday.
Flemings Left Hand Rule	Helps to know direction of motion of a current  conductor when placed in a magnetic field
Flemings Right Hand Rule	Helps to know direction of current induced in a conductor when moved in a magnetic field
Domestic         Circuit	Red Wire: +ve, Black Wire= -Ve, Green Wire= Earth

Q. Why does a compass needle get deflected when bought near a bar magnet?

Ans: The compass needle is a small magnet with one end acting as North pole and other as South pole.

When it is bought near a bar magnet, the needle gets deflected due to attraction or replusion.

Q. What is Magnetic Field? List three sources of Magnetic Field?    

Ans: Magnetic field is the space around a magnetic material where it exerts its magnetic force.

The three sources of magnetic field are bar magnet, solenoid, current carrying conductor.

Q. Draw magnetic field lines around bar magnet?

Ans: The magnetic field lines around a bar magnet are given below;

Q. State direction of magnetic field inside a bar magnet.

Ans: The direction of the magnetic field inside a bar magnet is from the south pole to the north pole.

Q. List the properties of magnetic lines of force.

Ans: Properties of Magnetic lines of force are:

(i) Magnetic lines of force start from the north pole and travel to the south pole outside the magnet.
(ii) They travel from South to North inside the magnet
(iii) They never intersect each other
(iv) Their magnitude decreases as we move away from the magnet.

Q. Why don't two magnetic lines of force intersect each other?

Ans: The two magnetic lines of force do not intersect each other because at the point of intersection the compass needle then must have to point towards two directions, which is not possible.

Q. What are conclusions of Oersted's experiment.

Ans: Hans Christian Oersted performed an experiment in 1820 which helped us to understand that the electricity and magnetism are related.

Oersted concluded that the current carrying conductor produces a magnetic field around it.

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

Ans: In this case as the current is flowing clockwise, On the left side, inside the loop the direction of magnetic field lines are going into the table  while outsidevthe loop,  magnetic field lines are coming out of the table.

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

Ans: When the magnetic field in a given region is uniform, it is called uniform magnetic magnetic field.

The magnetic lines are equidistant and Parallel.

Q. State Fleming's left hand rule.

Ans: Flemings left hand rule states that if we stretch the thumb, fore finger and middle finger of our left hand in such a way that they are mutually perpendicular to each other like X, Y and Z axis of a graph.

The forefinger represents points towards magnetic field, the middle finger points towards direction of current, then thumb points towards direction of motion of the conductor.

Q. What is the principle of an electric motor?

Ans: The principle of electric motor is based on Fleming's left hand rule. When a current carrying coil is placed in a uniform magnetic field  it experiences force which rotates the coil.

The electric motor converts electrical energy into mechanical energy.


Q. What is the role of split ring in an electric motor?

Ans: The split rings in a D.C motor reverses the direction of currect in the coil.
It is necessary to reverse the direction of direction of current to keep motor rotating in same direction.

Q. Explain the different ways to induce current in a coil?

Ans: The are many ways to induce current in a coil e.g;
1. By relative motion between the coil and a magnet i.e either moving a coil or magnet or both.
2. By changing the current in the neighbouring circuit.


Q. State the principle of an electric generator?

Ans: The Electric generator works on the principle of electromagnetic induction.


Q. Name some sources of direct current?

Ans: Some sources of direct current are: i. Cell  ii. Battery  iii. D.C. Generator


Q. Name sources producing alternating current?
Ans: Alternating current is produced by A.C generators like Hydro generators, wind turbines.

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

Ans: The safety measures commonly used in electric circuits and appliances are Electric fuse, MCB, Earth wire etc.

               

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

Ans: Following precautions should be taken to avoid the overloading of domestic electric circuits:

1. Wires of appropriate power rating and good insulation should be used.
2. There should be seperate circuit for heating appliances.
3. Fuse or MCB should be installed.

Q. List three sources of magnetic fields.

Ans: The three sources of magnetic field are:
1. Magnet
2. Current carrying conductor
3. Current carrying solenoid


Q. 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 bar magnet? Explain.

                                                       Or

 Draw a pattern of magnetic field lines around a current carrying solenoid.

Ans: A solenoid is a coil with number of turns of insulated copper wire wound in the form of cylinder.

When current flows through a solenoid it behaves like a magnet with magnetic field lines similar to a bar magnet.

One end of solenoid behaves as north pole and other end behaves as south pole.

When the north end of a bar magnet is bought near one end of solenoid and gets attracts, that that is South pole of Solenoid. If it gets repelled that that is North pole of bar magnet.

Q. State the factors on which the strength of magnetic field produced by a current carrying solenoid depend.

Ans: A solenoid is a coil with number of turns of insulated copper wire wound in the form of cylinder.

Factors:

The strength of magnetic field depends on the current flowing through the solenoid

The strength of magnetic field depends on the number of turns of the solenoid

Q. What is Right hand thumb rule ?

Ans: Right hand thumb rule helps determine Magnetic field around a straight current carrying conductor. If the thumb is placed in the direction of current, the fingers show the direction of magnetic field as shown in figure: 

Q. What is Electromagnet? State two points of difference between electromagnet and a permanent magnet

Ans: An electromagnet is a temporary magnet which acts as a magnet as long as electricity passes through it e.g. Solenoid

Electromagnet	Permanent magnet
It is made of soft iron	It is made of hard iron
Its strength can be changed	It has fixed strength
It is temporary magnet	It is permanent magnet
E.g Solenoid	E.g Bar magnet

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

Ans: When the current carrying conductor is perpendicular to the magnetic field, it experiences the largest force.


Q. Imagine you are sitting in a chamber with your back to one wall. An electron beam moving horizontally from the 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 should be in downwards direction according to Fleming's left hand rule.


Q. Draw a labelled diagram of an electric motor. Explain its principle and working.

Ans:

Principle: When a current carrying conductor is placed in a uniform magnetic field, it experiences force which rotates the coil. 

Diagram: 

Working:  An electric motor contains an Electric coil ABCD, placed between two Poles of a magnet.

The ends of Coil ABCD are connected to split ring at P and Q, which inturn is connected to Brushes at X and Y.

When current flows in the circuit, it flows from A to B and C to D.

As per Fleming's left rule, the AB side of coil faces downward force and CD side of coil faces Upward force.

After a half rotation, the current is reversed in the coil and it moves from D to C and B to A because to Split ring.

This reversal in direction of current keeps the motor moving in same direction.


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

Ans: Electric motors are used in many devices such as Washing machines, Mixers, Fans, Computers, Vehicles etc.


Q. A coil of insulated copper wire is connected to a galvanometer. What will happen if the bar magnet is
(i) Pushed into the coil
(ii) Withdrawn from inside the coil
(iii) Held stationary in the coil


Ans:
I. When bar magnet is pushed into the coil, there will be deflection in Galvanometer.
II. When bar magnet is withdrawn from the coil, there will be deflection in opposite direction.
III. When bar magnet is held stationary in the coil, there will be no deflection.


Q. Two circular coils A and B are placed close to each other. If the current in coil A is changed, Will some current be induced in Coil B? Give reasons.

Ans: If the current in coil A is changed, some current will be induced in Coil B due to electromagnetic Induction.


Q. State the rule to determine the direction of
I. Magnetic field around  a straight current carrying conductor.
II.  Force experienced by a current carrying straight conductor placed in a magnetic field which is perpendicular to it.
III. Current induced in a coil due to its rotation in a magnetic field.

Ans:
I. Magnetic field around a straight current carrying conductor is given by Right hand thumb rule.

II. Force experienced by by a current carrying straight conductor placed in a magnetic field which is perpendicular to it is given by Fleming's left hand rule.

III. Current induced in a coil due to its rotation in a magnetic field is given by Fleming's right hand rule.



Q. Explain the underlying principle and working of an electric generator by drawing a labeller diagram.

Ans:
Principle: Electric generator works on the principle of Electromagnetic Induction. In an electric generator, mechanical energy is converted into electric energy. 

Diagram:

Working:
Electric generator contains a rectangular coil ABCD placed between two poles of magnet. The coil is attached to two rings R1 and R2 which inturn are attached with brushes B1 and B2 respectively.

The rings are attached to an Axle which on rotation moves the coil along with it.

When Axle is rotated, the AB side of coil moves up and CD side moves down. Due to the motion, an Induced current is set in the coil. The current moves in ABCD direction.

After half rotation, CD moves up and AB moves down. The current moves in reverse direction DCBA direction based on Fleming's Right hand thumb rule.

Thus after every half rotation, the polarity of current changes. This is also called A.C generator.
In DC generator, Split ring is used instead of Rings.

Q. What is the function of brushes in electric generator?

Ans: The function of brushes in an electric generator is to transfer Electricity from Coil to outer circuit.

Q. When does an electric short circuit occur?

Ans: Electric short circuit occurs when the Live wire comes in contact with Neutral wire.
This can happen if the insulation around the wire gets removed.


Q. What is the function of earth wire? Why is it mecessary to earth metallic appliances?

Ans:  Earth wire is a wire with low resistance that prevents live wire overloading and current leakage through the ground.

A metallic body of high power rating electrical equipment is earthed by Earth wire that protects us from electric shocks.

Q.  The wires in a domestic circuit are coloured as Red, Green & Black? What does it indicate.

Ans: The Red coloured wire is Live wire,
The Green Colour wire is Earth Wire
The Black Colour wire is neutral

Mark the answers of below Questions  as shown below;
A. Both Assertion and Reason is True and Reason correctly explains Assertion
B. Both Assertion and Reason is True and Reason is not correct explanation of Assertion
C. Assertion is True, Reason is False
D. Assertion is False, Reason is True

Q. Assertion(A): On changing the direction of flow of current through a straight conductor, the direction of a magnetic field around the conductor is reversed.

Reason (R) : The direction of magnetic field around a conductor can be known by left hand thumb rule.

Ans: C. Assertion is True, Reason is False

Q. Assertion (A) : Electromagnets are made of solenoid wound around soft iron core
Reason (R) : The strength of an electromagnet is increased by increasing the current flowing through the solenoid coil.

Ans: B. Both A and R are true, But R is not correct explanation of A

Q. Assertion : The magnetic field inside the solenoid is uniform.
Reason : The magnetic field produced by a current carrying solenoid is depends on number of turns and current supplied

Ans: B. Both A and R are true, But R is not correct explanation of A

Q. What are electric field lines. Give their properties?

Ans: Electric field lines are lines or curves that show electric field around the charges.

They are similar properties as magnetic field lines.

Properties:

Electric field lines start from the positive charge (+) and end at Negative charge (-)

They never intersect each other

They do not pass through a conductor

Objective Type Questions:

Q. Which of the following property of proton can change while it moves freely in a magnetic field?

A.  Mass    B. Speed     C.   Velocity    D. Momentum


Ans: Velocity and momentum

Q. A positive charged particle  emitted from nucleus alpha particle projected towards west is deflected towards north by magnetic field. The direction of magnetic field is

A. South                B. East
C. Downwards       D. Upwards

Ans:
D. Upwards

Q. What is principal of electric motor?

Ans: When current carrying coil is placed in magnetic field, It feels torque which rotate the coil.

Q. What is role of split ring in an electric motor?

Ans: The split ring reverse direction of current after half cycle.

Q. Name sources of direct current?

Ans: Cell, Battery,  D.C Generator.

Q. Which sources produce alternating current?

Ans: A.C generators.

Q. A rectangular coil of copper wires is rotated in magnetic field. The direction of induced current changes once in each:

A. Two revolutions   B. One Revolution
C. Half Revolution   D. One fourth revolution

Ans: Half Revolution.

Q. Which of following correctly describe magmetic lines near a long wire? The field consists of

a. Straight lines
b. Radial lines
c. Concentric circle centred on wire

Ans: c. Concentric circle centred on wire


Q. The phenomenon of electro magnetic induction is:
A. Process of charging a body
B. Process of generating magnetic field
C. Producing induced current in a coil
D. Process of rotating coil of motor

Ans: C. Producing induced current in a coil.

Q. The device used for producing electric current is called:
A. Generator  B. Galvanometer
   C. Ammeter        D. Motor

Ans: a. Generator

Q. The Essential difference between A.C generator and D.C generator is

A. D.C generator has higher voltage
B. A.C generator has higher voltage
C. AC generator has slip rings while DC generator has commutator

Ans: AC generator has slip rings while DC generator has commutator

Q. At the time of short circuit, the current in circuit;

A. Reduces    B. No change    C. Increases  heavily     D. Vary

Ans: C. Increases  heavily  

Q. Which of following is based on electromagnetic induction

A. Galvanometer    B. Transformer
C. X rays                  D. Voltmeter

Ans: B. Transformer

Q. When current flows in a wire, It produces:

A. Electric field
B. Magnetic field
C. Both electric and magnetic field

Ans: C. Both electric and magnetic field

Q. When coil is kept stationary relative to magnetic, the galvanometer gives deflection:

A. Maximum    B. Zero     C. Constant  

Ans: Zero

Q. Which among the following is used to find direction of magnetic field line around a current carrying straight conductor?

I. Amperes swimming rule
II. Fleming's right hand thumb rule
III. Fleming's left hand thumb rule
IV. Faradays rule

Ans: II. Fleming's right hand thumb rule.


Q. Magnitude of magnetic field around a current carrying conductor at any point is:

I. Directly proportional to intensity of electric current
II. Inversely proportional to the distance of conductor
III. Directly proportional to the distance of conductor
IV. Both A & B

Ans: Both A & B


   Q. To find the direction of deflection of compass needle due to magnetic field of current carrying conductor, we use

I. Amperes swimming rule
II. Fleming's right hand thumb rule
III. Fleming's left hand thumb rule
IV. Faradays rule


Ans: I. Amperes swimming rule


Q. Current carrying conductor is a

I. Permenant magnet
II. Temporary magnet
III. Natural magnet
IV. None of these

Ans: II. Temporary magnet

Q. Which among the following produces strong magnetic field?

I. Permenant magnet
II. Natural magnet
III. Bar magnet
IV. Electromagnet


Ans: IV: Electromagnet

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


Q . 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: C. producing induced current in a coil due to relative motion between a magnet and the coil


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

A. generator
B. galvanometer
C. ammeter
D. motor

Ans: A. generator

Q. 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: D. AC generator has slip rings while the DC generator has a commutator.



Q. 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: C.  Increases heavily

Q. Which statement among the following is true for electric motor. 

A. It generates electric current.

B. It converts electric energy into mechanical energy.

C. It converts mechanical energy into electric energy.

D. Both A and B 

Ans: B. It converts electric energy into mechanical energy.

Q. Which of following is responsible to reverse the direction of current in the armature coil? 

A. Split rings

B. Brushes

C. Shaft

D. None of these 

Ans: A. Split Rings

Q. The motion produced in the arms of armature coil can be explained by applying: 

A. Maxwells right hand thumb rule

B. Fleming's right hand rule

C. Fleming's left hand rule

D. Clock rule 

Ans: C. Fleming's left hand rule 

Q. The speed of rotation of armature can be increased by: 

A. Increasing the strength of current

B. Increasing the strength of magnetic field 

C. Increasing the number of turns in the coil of armature

D. All of these. 

Ans: D. All of these.

Q. In an electric motor the direction of electric current and magnetic field are: 

A. Parallel to each other

B. Mutually perpendicular to each other

C. Opposite to each other

D. None of these

Ans:  B. Mutually perpendicular to each other 

Q. The current carrying conductor in a magnetic field experiences force only : 

A. When it is placed parallel to magnetic field

B. When it is placed perpendicular to magnetic field

C. When it is placed outside the magnetic field

D. None of these

Ans: B. When it is placed perpendicular to magnetic field

Q. The force acting on the conductor placed in a magnetic field is proportional to the 

A. Current flowing through the conductor

B. Length of conductor inside the magnetic field

C. Magnitude of the magnetic field

D. All of the above

Ans: D. All of the above

Q. In kicking wire experiment, the current, magnetic field and the direction of the force on the wire are: 

A. Parallel to each other

B. Mutually at right angles to each other 

C. Have no particular direction

D. None of these

Ans: B. Mutually at right angles to each other

Q. The direction of force on current carrying conductor in a magnetic field is given by 

A. Maxwell’s right hand thumb rule

B. Flemings right hand rule

C. Fleming's left hand rule

D. Amperes swimming rule

Ans: C. Fleming's left hand rule

Q. Which of following works on the principle of kicking wire experiment? 

A. Electric motor

B. AC generator

C. DC generator

D. All of above

Ans: A. Electric motor.

Q. When we compare magnetic field lines of the solenoid with field pattern of cylindrical bar magnet. It is found that, 

A. Magnetic field lines are identical

B. Magnetic field lines have different pattern

C. Current carrying solenoid behaves like a bar magnet with fixed polarities

D. Both A and C 

Ans: D. Both A and C

Q. The magnetic field lines inside a solenoid is: 

A. Uniform 

B. Non uniform

C. Can be uniform or Non uniform

D. None of above

Ans: A. Uniform

Q. The current carrying solenoid has;

A. Attractive properties only

B. Directive properties only

C.  Both attractive and directive properties

D. None

Ans: C  Both attractive and directive properties

Q. Current carrying Solenoid behaves as a 

A. Temporary strong magnet

B. Permanent strong magnet

C. Temporary weak magnet

D. Permanent weak magnet

Ans: A. Temporary strong magnet

Q. The magnitude of magnetic field by the solenoid depends on, 

A. Current flowing through the solenoid

B. Number of turns per unit length of solenoid

C. Both A and B

D. None 

Ans: C. Both A and B

Q. State Fleming’s left-hand rule.

Ans: Fleming's left-hand rule is used to find the direction of the force acting on the current carrying conductor placed in a magnetic field.

It states that  if we arrange our thumb, forefinger and middle finger of the right-hand perpendicular to each other, then the thumb points towards the direction of the motion of the conductor relative to the magnetic field, the forefinger points towards the direction of the magnetic field and the middle finger points towards the direction of the induced current.

 

 

Q. Out of A.C generator and a D.C generator, which one uses a commutator?

Ans: An D.C generator uses commutator.

Q. Out of A.C generator and  a D.C generator, which one uses slip rings?

Ans: An A.C generator uses Slip rings.

 

Q. What is magnetic field? State any two properties of magnetic field lines?

Ans: The magnetic field is a vector field that describes magnetic influence of the charges and magnetic materials.

Two properties of magnetic field lines are:

1. They never cross each other.

2. They flow from North to south pole outside the magnet.

 

Q. What type of generator is used at power stations?

Ans: A.C generator is used in power stations.

 

Q. What is the principle of electric motor? Name two devices in which electric motor is used?

Ans: Electric motor works on the principle of Flemings Left hand rule.

Electric motors are used in water pumps, electric fans, electric mixers etc.

Q. Which among 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 concentric circles centred on the wire
D. Both A and B
Ans: C. The field consists of concentric circles centred on the wire

Q. Every current carrying conductor produces magnetic field, this phenomenon was discovered by:
A. Maxwell B. Oersted C. Faraday D. Coulomb
Ans: Oersted

Q. The direction of magnetic field around a current carrying straight conductor can be determined by:
A. Flemings right hand rule B. Flemings left hand rule
C. Faradays Rule D. Right hand thumb rule
Ans: Flemings right hand rule

Q. The magnitude of magnetic field produced by a current carrying straight conductor is:
A. Directly proportional to the Intensity of current
B. Directly proportional to the distance from conductor
C. Inversely proportional to distance from the conductor
D. Both A and C
Ans: D. Both A and C

Q. If the direction of electric current in a current carrying conductor is upwards, the direction of magnetic field lines will be:
A. Clock wise B. Anticlockwise C. Both A and B D. Can’t be determined
Ans: B. Anticlockwise

6.   Assertion (A): Magnetic field lines don't intersect each other

Reason (R): Magnetic field lines are imaginary lines, the tangents to which any point gives the direction of the field at that point.

A and R are true and R is correct explanation of A

Both A and Rare true and R is not correct explanation of A

A is true but R is false

A is false but R is true

 

Ans: A and R are true and R is correct explanation of A

Q. Magnitude of a magnetic field around a current carrying conductor at any point is:

a. Directly proportional to the intensity of electric current

b. Inversely proportional to the distance from the conductor

c. Directly proportional to the distance from the conductor

d. Both A and B

Ans: d. Both A and B





Q. Assertion: When a current carrying conductor is placed in a magnetic field, It experiences a force

Reason: The force acting on a current carrying conductor is only due to the external magnetic field.

A. Both A and R are true and R is the correct explanation of A

B. Both A and R are true and R is not the correct explanation of A

C. A is True, R is False

D. A is False, R is True

Ans: C. A is True, R is False

Hint: The force acting on the conductor is due to the interaction of external magnetic field and the magnetic field produced due to the current flowing in the conductor



Q. Assertion: When a compass needle is moved away from a current carrying straight conductor, the deflection of the needle decreases

Reason: The strength of magnetic field decreases on moving away from the conductor

A. Both A and R are true and R is the correct explanation of A

B. Both A and R are true and R is not the correct explanation of A

C. A is True, R is False

D. A is False, R is True

Ans: A. Both A and R are true and R is the correct explanation of A



Q. Assertion: When the direction of current in a current carrying straight conductor is upwards, the direction of magnetic field lines is clockwise

Reason: To find the direction of magnetic field lines, we use maxwells right hand thumb rule

A. Both A and R are true and R is the correct explanation of A

B. Both A and R are true and R is not the correct explanation of A

C. A is True, R is False

D. A is False, R is True

Ans: D. A is False, R is True



Q. To find out the direction of deflection of the compass needle due to magnetic field of a current carrying conductor, we use:

a. Amperes swimming rule b. Flemings right hand rule

c. Maxwells Rule d. Flemings left hand rule

Ans: a. Amperes swimming rule



Q. Which among the following is used to find the direction of magnetic field lines around a current carrying straight conductor ?

a. Amperes swimming rule          b. Flemings right hand rule

c. Maxwells right hand thumb rule   d. Flemings left hand rule

Ans: c. Maxwells right hand thumb rule

Q. Which property of a proton can change while it moves freely in a magnetic field?

(A) Mass and speed (B) Speed and velocity  (C) Mass and momentum (D) Velocity and momentum

Ans: (D) Velocity and momentum

Q. A rectangular coil of copper wires is rotated in a magnetic field. The direction of the induced current changes once in each:

(A) Two revolutions (B) One revolution (C) Half revolution  (D) One-fourth revolution

Ans: (C) Half revolution  

 

 

                     ......................

Glimpse of Fit India School Week at Govt H.S Amad