A solenoid is a long coil of circular loops of insulated copper wire. Magnetic field lines are produced around the solenoid when a current is allowed to flow through it. The field lines produced in a current-carrying solenoid is shown magnetic field line emerges from North pole towards South pole, wRead more
A solenoid is a long coil of circular loops of insulated copper wire. Magnetic field lines are produced around the solenoid when a current is allowed to flow through it. The field lines produced in a current-carrying solenoid is shown magnetic field line emerges from North pole towards South pole, whereas inside the solenoid magnetic field lines parallel.
When the north pole of a bar magnet is brought near the end to the negative terminal of the battery, the solenoid repels the bar magnet as like poles repel each other, the end connected to the negative terminal of the battery behaves as the north pole of the solenoid and the other end behaves as a south pole. So, one end of the solenoid behaves as a north pole and the other end behaves as a south pole.
The direction of the magnetic field is determined by Fleming’s left hand rule. Magnetic field inside the chamber will be perpendicular to the direction of current and direction of deflection either upward or downward. The direction of current is from the front wall to the back wall because negativelRead more
The direction of the magnetic field is determined by Fleming’s left hand rule. Magnetic field inside the chamber will be perpendicular to the direction of current and direction of deflection either upward or downward. The direction of current is from the front wall to the back wall because negatively charged electrons are moving from the back wall to the front wall. The direction of magnetic force is rightward. By using Fleming’s left hand rule, it can be concluded that the direction of magnetic field inside the chamber is downward.
An electric motor converts electrical energy into mechanical energy. Electric motor is based on the principle of the magnetic effect of current. A current-carrying coil rotates in a magnetic field. When a current is allowed to flow through the coil MNST by closing the switch, the coil starts rotatinRead more
An electric motor converts electrical energy into mechanical energy.
Electric motor is based on the principle of the magnetic effect of current. A current-carrying coil rotates in a magnetic field. When a current is allowed to flow through the coil MNST by closing the switch, the coil starts rotating anti-clockwise. This happens because a downward force acts on length MN and at the same time, an upward force acts on length ST. As a result, the coil rotates anti-clockwise.
Current in the length MN flows from M to N and the magnetic field acts from left to right, normal to length MN. Therefore, according to Fleming’s left hand rule, a downward force acts on the length MN. Similarly, current in the length ST flows from S to T and the magnetic field acts from left to right, normal to the flow of current. Therefore, an upward force acts on the length ST. These two forces cause the coil to rotate anti-clockwise.
After half a rotation, the position of MN and ST interchange. The half-ring D comes in contact with brush A and half-ring C comes in contact with brush B. Hence, the direction of current in the coil MNST gets reversed.
The current flows through the coil in the direction TSNM. The reversal of current through the coil MNST 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 are called the commutator.
A current induces in a solenoid if 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 of insulated copper wire, a current is induced in the coil. As a result of which the needle of the galvanometer deflects directionRead more
A current induces in a solenoid if 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 of insulated copper wire, a current is induced in the coil. As a result of which the needle of the galvanometer deflects direction of current.
(ii) When the bar magnet is withdrawn from inside the coil of the insulated copper wire, a current is again induced in the coil in the opposite direction. As a result, the needle of the galvanometer deflects in the opposite direction.
(iii) When a bar magnet is held stationary inside the coil, no current will be induced in the coil. So, no deflection in the galvanometer.
Two circular coils A and B are placed close to each other. When the current in coil A is changed, the magnetic field associated with it also changes. As a result, the magnetic field around coil B also changes. This change in magnetic field lines around coil B induces an electric current in it. ThisRead more
Two circular coils A and B are placed close to each other. When the current in coil A is changed, the magnetic field associated with it also changes. As a result, the magnetic field around coil B also changes. This change in magnetic field lines around coil B induces an electric current in it. This is called electromagnetic induction.
(i) Right hand thumb rule : If the current carrying conductor is held in the right hand such that the thumb points in the direction of the current, then the direction of the curl of the fingers will give the direction of the magnetic field. (ii) Fleming’s left hand rule : NCERT Solutions for Class 1Read more
(i) Right hand thumb rule : If the current carrying conductor is held in the right hand such that the thumb points in the direction of the current, then the direction of the curl of the fingers will give the direction of the magnetic field. (ii) Fleming’s left hand rule : NCERT Solutions for Class 10 Science Chapter 13 Magnetic Effects of Electric Current Stretch the forefinger, the central finger and the thumb of the left hand mutually perpendicular to each other. If the forefinger points in the direction of the magnetic field, the middle finger in the direction of current, then the thumb points in the direction of force in the conductor. (iii) Fleming’s right hand rule : Stretch the thumb, forefinger and the central finger of the right hand mutually perpendicular to each other. If the forefinger points in the direction of magnetic field, thumb in the direction of motion of the conductor, then the middle finger points in the direction of current induced in the conductor.
Principle : The electric generator is based on the principle of electromagnetic induction. When a coil is rotated with respect to a magnetic field, the number of magnetic field lines through the coil changes. Due to this a current is induced in the coil whose direction can be found by Fleming’s righRead more
Principle : The electric generator is based on the principle of electromagnetic induction. When a coil is rotated with respect to a magnetic field, the number of magnetic field lines through the coil changes. Due to this a current is induced in the coil whose direction can be found by Fleming’s right hand rule.
Working : When the armature coil ABCD rotates in a magnetic field produced by the permanent magnets, it cuts through the magnetic lines of force. Due to the rotation of armature coil, the associated magnetic field changes and an induced electromagnetic force is produced in it. The direction of this induced electromotive force or current can be determined by using Fleming’s right hand rule. In first half cycle the current flows in one direction by brush B1 and in second it flows in opposite direction by brush B2. This process continues. So the current produced is alternating in nature. Functions of Brushes : Brushes in contact with rings provide the current for external use.
When neutral wire and live wire touch each other that they come in direct contact, the resistance of the circuit becomes small and a large amount of current flows through it. As a result of which, a large amount of heat is produced and the circuit catches fire.
When neutral wire and live wire touch each other that they come in direct contact, the resistance of the circuit becomes small and a large amount of current flows through it. As a result of which, a large amount of heat is produced and the circuit catches fire.
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.
A solenoid is a long coil of circular loops of insulated copper wire. Magnetic field lines are produced around the solenoid when a current is allowed to flow through it. The field lines produced in a current-carrying solenoid is shown magnetic field line emerges from North pole towards South pole, wRead more
A solenoid is a long coil of circular loops of insulated copper wire. Magnetic field lines are produced around the solenoid when a current is allowed to flow through it. The field lines produced in a current-carrying solenoid is shown magnetic field line emerges from North pole towards South pole, whereas inside the solenoid magnetic field lines parallel.
When the north pole of a bar magnet is brought near the end to the negative terminal of the battery, the solenoid repels the bar magnet as like poles repel each other, the end connected to the negative terminal of the battery behaves as the north pole of the solenoid and the other end behaves as a south pole. So, one end of the solenoid behaves as a north pole and the other end behaves as a south pole.
See lessWhen is the force experienced by a current–carrying conductor placed in a magnetic field largest?
When the direction of current is perpendicular to the direction of magnetic field. The force experienced by the current carrying conductor is maximum.
When the direction of current is perpendicular to the direction of magnetic field. The force experienced by the current carrying conductor is maximum.
See lessImagine 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?
The direction of the magnetic field is determined by Fleming’s left hand rule. Magnetic field inside the chamber will be perpendicular to the direction of current and direction of deflection either upward or downward. The direction of current is from the front wall to the back wall because negativelRead more
The direction of the magnetic field is determined by Fleming’s left hand rule. Magnetic field inside the chamber will be perpendicular to the direction of current and direction of deflection either upward or downward. The direction of current is from the front wall to the back wall because negatively charged electrons are moving from the back wall to the front wall. The direction of magnetic force is rightward. By using Fleming’s left hand rule, it can be concluded that the direction of magnetic field inside the chamber is downward.
See lessDraw a labelled diagram of an electric motor. Explain its principle and working. What is the function of a split ring in an electric motor?
An electric motor converts electrical energy into mechanical energy. Electric motor is based on the principle of the magnetic effect of current. A current-carrying coil rotates in a magnetic field. When a current is allowed to flow through the coil MNST by closing the switch, the coil starts rotatinRead more
An electric motor converts electrical energy into mechanical energy.
Electric motor is based on the principle of the magnetic effect of current. A current-carrying coil rotates in a magnetic field. When a current is allowed to flow through the coil MNST by closing the switch, the coil starts rotating anti-clockwise. This happens because a downward force acts on length MN and at the same time, an upward force acts on length ST. As a result, the coil rotates anti-clockwise.
Current in the length MN flows from M to N and the magnetic field acts from left to right, normal to length MN. Therefore, according to Fleming’s left hand rule, a downward force acts on the length MN. Similarly, current in the length ST flows from S to T and the magnetic field acts from left to right, normal to the flow of current. Therefore, an upward force acts on the length ST. These two forces cause the coil to rotate anti-clockwise.
After half a rotation, the position of MN and ST interchange. The half-ring D comes in contact with brush A and half-ring C comes in contact with brush B. Hence, the direction of current in the coil MNST gets reversed.
The current flows through the coil in the direction TSNM. The reversal of current through the coil MNST 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 are called the commutator.
See lessName some devices in which electric motors are used.
The devices in which electric motors are used are as follows: a. Electric mixers b. Water pumps c. Washing machines d. Electric fans
The devices in which electric motors are used are as follows:
a. Electric mixers
See lessb. Water pumps
c. Washing machines
d. Electric fans
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?
A current induces in a solenoid if 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 of insulated copper wire, a current is induced in the coil. As a result of which the needle of the galvanometer deflects directionRead more
A current induces in a solenoid if 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 of insulated copper wire, a current is induced in the coil. As a result of which the needle of the galvanometer deflects direction of current.
(ii) When the bar magnet is withdrawn from inside the coil of the insulated copper wire, a current is again induced in the coil in the opposite direction. As a result, the needle of the galvanometer deflects in the opposite direction.
(iii) When a bar magnet is held stationary inside the coil, no current will be induced in the coil. So, no deflection in the galvanometer.
See lessTwo 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.
Two circular coils A and B are placed close to each other. When the current in coil A is changed, the magnetic field associated with it also changes. As a result, the magnetic field around coil B also changes. This change in magnetic field lines around coil B induces an electric current in it. ThisRead more
Two circular coils A and B are placed close to each other. When the current in coil A is changed, the magnetic field associated with it also changes. As a result, the magnetic field around coil B also changes. This change in magnetic field lines around coil B induces an electric current in it. This is called electromagnetic induction.
See lessState 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.
(i) Right hand thumb rule : If the current carrying conductor is held in the right hand such that the thumb points in the direction of the current, then the direction of the curl of the fingers will give the direction of the magnetic field. (ii) Fleming’s left hand rule : NCERT Solutions for Class 1Read more
(i) Right hand thumb rule : If the current carrying conductor is held in the right hand such that the thumb points in the direction of the current, then the direction of the curl of the fingers will give the direction of the magnetic field.
See less(ii) Fleming’s left hand rule : NCERT Solutions for Class 10 Science Chapter 13 Magnetic Effects of Electric Current Stretch the forefinger, the central finger and the thumb of the left hand mutually perpendicular to each other. If the forefinger points in the direction of the magnetic field, the middle finger in the direction of current, then the thumb points in the direction of force in the conductor.
(iii) Fleming’s right hand rule : Stretch the thumb, forefinger and the central finger of the right hand mutually perpendicular to each other. If the forefinger points in the direction of magnetic field, thumb in the direction of motion of the conductor, then the middle finger points in the direction of current induced in the conductor.
Explain the underlying principle and working of an electric generator by drawing a labelled diagram. What is the function of brushes?
Principle : The electric generator is based on the principle of electromagnetic induction. When a coil is rotated with respect to a magnetic field, the number of magnetic field lines through the coil changes. Due to this a current is induced in the coil whose direction can be found by Fleming’s righRead more
Principle : The electric generator is based on the principle of electromagnetic induction. When a coil is rotated with respect to a magnetic field, the number of magnetic field lines through the coil changes. Due to this a current is induced in the coil whose direction can be found by Fleming’s right hand rule.
Working : When the armature coil ABCD rotates in a magnetic field produced by the permanent magnets, it cuts through the magnetic lines of force. Due to the rotation of armature coil, the associated magnetic field changes and an induced electromagnetic force is produced in it. The direction of this induced electromotive force or current can be determined by using Fleming’s right hand rule. In first half cycle the current flows in one direction by brush B1 and in second it flows in opposite direction by brush B2. This process continues. So the current produced is alternating in nature.
See lessFunctions of Brushes : Brushes in contact with rings provide the current for external use.
When does an electric short circuit occur?
When neutral wire and live wire touch each other that they come in direct contact, the resistance of the circuit becomes small and a large amount of current flows through it. As a result of which, a large amount of heat is produced and the circuit catches fire.
When neutral wire and live wire touch each other that they come in direct contact, the resistance of the circuit becomes small and a large amount of current flows through it. As a result of which, a large amount of heat is produced and the circuit catches fire.
See less