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प्रश्न
State two ways to increase the speed of rotation of a D.C. motor.
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उत्तर
By increasing the magnetic flux [by using strong magnet]
By reducing number of turns in the winding.
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संबंधित प्रश्न
The magnetic field inside a long straight solenoid-carrying current ______.
Which of the following property of a proton can change while it moves freely in a magnetic field? (There may be more than one correct answer.)
Draw the magnetic lines of force due to a circular wire carrying current.
Name one device whose working depends on the force exerted on a current-carrying coil placed in a magnetic field.
Two coils A and B of insulated wire are kept close to each other. Coil A is connected to a galvanometer while coil B is connected to a battery through a key. What would happen if:
the current is stopped by removing the plug from the key?
Explain your answer mentioning the name of the phenomenon involved.
Name three factors on which the magnitude of force on a current carrying conductor placed in a magnetic field depends and state how does the force depend on the factors stated by you.
Name and state the law which is used to determine the direction of force on a current carrying conductor placed in a magnetic field.
A flat coil ABCD is freely suspended between the pole of U-shaped permanent magnet with the plane of coil parallel to the magnetic field.
What happens when a current is passed in the coil?
The following diagram shows two parallel straight conductors carrying the same current. Copy the diagram and draw the pattern of the magnetic field lines around them showing their directions. What is the magnitude of the magnetic field at a point 'X' which is equidistant from the conductors? Give justification for your answer.
Which of the following pattern correctly describes the magnetic field around a long straight wire carrying current?
