Advertisements
Advertisements
प्रश्न
State two ways to increase the speed of rotation of a D.C. motor.
Advertisements
उत्तर
By increasing the magnetic flux [by using strong magnet]
By reducing number of turns in the winding.
APPEARS IN
संबंधित प्रश्न
Imagine 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?
State and explain the Clock face rule for determining the polarities of a circular wire carrying current.
Name the type of magnet with which the magnetic field pattern of a current-carrying solenoid resembles
The front face of a circular wire carrying current behaves like a north pole. The direction of current in this face of circular wire is:
(a) clockwise
(b) downwards
(c) anticlockwise
(d) upwards
A current-carrying conductor is placed perpendicularly in a magnetic field. Name the rule which can be used to find the direction of force acting on the conductor.
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:
a current is passed through coil B by plugging the key?
Explain your answer mentioning the name of the phenomenon involved.
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 under what conditions force acting on a current carrying conductor which is freely suspended in a magnetic field can be Zero.
Assertion (A): A current carrying straight conductor experiences a force when placed perpendicular to the direction of magnetic field.
Reason (R): The net charge on a current carrying conductor is always zero.
