Advertisements
Advertisements
प्रश्न
State three factors which govern the speed of rotation of an electric motor.
उत्तर
(i) The strength of current in the coil,
(ii) The number of turns in the coil,
(iii) The strength of the magnetic field.
APPEARS IN
संबंधित प्रश्न
The diagram shows a coil wound around a U shape soft iron bar AB.
1) What is the polarity induced at the ends A and B when the switch is pressed?
2) Suggest one way to strengthen the magnetic field in the electromagnet
3) What will be the polarities at A & B if the direction of current is reversed in the circuit?
Show with the aid of a diagram how a wire is wound on a U-shaped piece of soft iron in order to make it an electromagnet. Complete the circuit diagram and label the poles of the electromagnet.
State two differences between an electromagnet and a permanent magnet.
principle of an electric motor ?
Complete the following sentence :
On reserving the direction of current in a wire, the magnetic field produced by it gets _____.
What is an electromagnet?
How does a magnetic field set up by a solenoid change when number of turns are increased?
How does a magnetic field set up by a solenoid change when a soft iron core is inserted inside solenoid?
What will be the effect on the working of an electric bell if instead of a direct current an alternating current is used?
A current-carrying solenoid is suspended so as to freely rotate in a horizontal plane. State in what direction will it rest. Give a reason for your answer.
or
When a solenoid that is carrying current is freely suspended, it comes to rest in a particular direction. Why does this happen?
