Advertisements
Advertisements
प्रश्न
Write some of the important uses of electromagnets.
Advertisements
उत्तर
- Electromagnets are used by doctors in MRI scanners.
- It is used for treating knee pain by using pulsing electromagnetic fields (PEMF).
- It is used in magnetic levitation trains.
संबंधित प्रश्न
Name two devices in which electromagnets are used and two devices where permanent magnets are used.
Consider the energy density in a solenoid at its centre and that near its ends. Which of the two is greater?
The following diagram shows a fixed coil of several turns connected to a center zero galvanometer G and a magnet NS which can move in the direction shown in the diagram.
- Describe the observation in the galvanometer if
- The magnet is moved rapidly,
- The magnet is kept still after it has moved into the coil
- The magnet is then rapidly pulled out the coil.
- How would the observation in (i) of part (a) change if a more powerful magnet is used?
List some of the practical applications of an electromagnet.
The diagram shows a rectangular coil ABCD, suspended freely between the concave pole pieces of a permanent horseshoe magnet, such that the plane of the coil is parallel to the magnetic field.
- State your observation when the current is switched on.
- Give an explanation for your observation in (i).
- State the rule, which will help you to find the motion of rotation of the coil.
- In which position will the coil ultimately come to rest?
- State four ways of increasing the magnitude of force acting on the coil.
State Lenz’s law.
State Fleming’s right-hand rule.
A square coil of side 30 cm with 500 turns is kept in a uniform magnetic field of 0.4 T. The plane of the coil is inclined at an angle of 30° to the field. Calculate the magnetic flux through the coil.
A coil of 200 turns carries a current of 0.4 A. If the magnetic flux of 4 mWb is linked with each turn of the coil, find the inductance of the coil.
What can produce a current in a coil even when the coil does not move?
