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प्रश्न
Draw figure ‘Electric motor’ and working
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उत्तर
Electric motor:
Working: 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.
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संबंधित प्रश्न
What is the Principle of an Electric motor?
Name any four appliances where electric motor is used.
State whether the following statement is true or false.
An electric motor converts mechanical energy into electrical energy.
Explain the function of the following parts of an electric motor.
Brushes
Explain the function of the following parts of an electric motor.
Split ring
Electric motor works on the magnetic effect of electric current.
A motor converts one form of energy into another. Name the two forms.
State whether the following statement is true or false:
An electric motor converts mechanical energy into electrical energy.
Name the device which is used to reverse the direction of current in the coil of a motor?
What is the other name of the split ring used in an electric motor?
What is the function of a commutator in an electric motor made ?
Of what substance are the brushes of an electric motor made?
In an electric motor, which of the following remains fixed and which rotates with the coil?
Commutator ; Brush
Fill in the following blank with suitable words:
A motor contains a kind of switch called a .......... which reverses the current every half .......... .
What is the principle of an electric motor?
In a d.c. motor, why must the current to the coil be reversed twice during each rotation?
State what would happen to the direction of rotation of a motor if:
the current were reversed
State what would happen to the direction of rotation of a motor if:
both current and magnetic field were reversed simultaneously.
State what would happen to the direction of rotation of a motor if:
In what ways can a motor be made more powerful?
In an electric motor, the direction of current in the coil changes once in each:
two rotations
one rotation
half rotation
one-four rotation
Tell the odd one out. Give a proper explanation.
Which device is used to produce electricity? Describe with a neat diagram.
Study the following principle and answer the question.
A force is excreted on the current carrying conductor. The direction of this force depends on both the direction of the current and the direction of the magnetic field. This force is maximum when the direction of current is perpendicular to the direction of the magnetic field.
a) By which law we can determine the direction of force excreted on the current carrying conductor.
b) In which electrical equipment this principle is used.
c) Draw a diagram representing construction of this equipment.
d) Write the working of this equipment in brief.
Name some of the devices in which electric motor are used.
Draw a labelled diagram of an electric motor.
Which of the following converts electrical energy into mechanical energy?
State whether true or false. If false, correct the statement.
The speed of rotation of an electric motor can be increased by decreasing the area of the coil.
List the main parts of an electric motor.
In an electric motor, to make the coil rotating continuously in the same direction, the current is reversed in the coil after every half rotation by a device called ____________.
Draw a labelled circuit diagram of a simple electric motor and explain its working. In what way these simple electric motors are different from commercial motors?
How can the speed of rotation of a coil be increased? Write at least three methods.
