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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
State Fleming’s left hand rule.
State the form of magnetic field lines around a straight current-carrying conductor.
Draw the magnetic lines of force due to a circular wire carrying current.
List three ways in which the magnetic field strength of a current-carrying solenoid can be increased?
A soft iron bar is inserted inside a current-carrying solenoid. The magnetic field inside the solenoid:
(a) will decrease
(b) will increase
(c) will become zero
(d) will remain the same
A horizontal wire carries a current as shown in Figure below between magnetic poles N and S:
Is the direction of the force on the wire due to the magnet:
(a) in the direction the current
(b) vertically downwards
(c) opposite to the current direction
(d) vertically upwards
A flat coil ABCD is freely suspended between the pole of a U-shaped permanent magnet with the plane of coil parallel to the magnetic field.
Name an instrument which makes use of the principle stated above.
State whether a magnetic field is associated or not around a moving charge.
State under what conditions force acting on a current carrying conductor which is freely suspended in a magnetic field can be Zero.
A current-carrying conductor of a certain length, kept perpendicular to the magnetic field experiences a force F. What will be the force if the current is increased four times, the length is halved and the magnetic field is tripled?
