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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
Consider a circular loop of wire lying in the plane of the table. Let the current pass through the loop clockwise. Apply the right-hand rule to find out the direction of the magnetic field inside and outside the loop.
The magnetic field inside a long straight solenoid-carrying current ______.
A positively-charged particle (alpha-particle) projected towards west is deflected towards north by a magnetic field. The direction of magnetic field is ______.
State Fleming’s left-hand rule.
A current-carrying conductor is held in exactly vertical direction. In order to produce a clockwise magnetic field around the conductor, the current should passed in the conductor:
(a) from top towards bottom
(b) from left towards right
(c) from bottom towards top
(d) from right towards left
The force experienced by a current-carrying conductor placed in a magnetic field is the largest when the angle between the conductor and the magnetic field is:
45°
60°
90°
180°
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
In the simple electric motor of figure given below, the coil rotates anticlockwise as seen by the eye from the position X when current flows in the coil
Is the current flowing clockwise or anticlockwise around the coil when viewed from above?
If the current in a wire is flowing in the vertically downward direction and a magnetic field is applied from west to east, what is the direction of force in the wire?
Describe the activity that shows that a current-carrying conductor experiences a force perpendicular to its length and the external magnetic field. How does Fleming’s left-hand rule help us to find the direction of the force acting on the current carrying conductor?
