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प्रश्न
Write some of the important uses of electromagnets.
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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
A horizontal straight wire 10 m long extending from east to west is falling with a speed of 5.0 m s−1, at right angles to the horizontal component of the earth’s magnetic field, 0.30 × 10−4 Wb m−2.
- What is the instantaneous value of the emf induced in the wire?
- What is the direction of the emf?
- Which end of the wire is at the higher electrical potential?
A light metal disc on the top of an electromagnet is thrown up as the current is switched on. Why? Give reason.
Consider the energy density in a solenoid at its centre and that near its ends. Which of the two is greater?
The switches in figure (a) and (b) are closed at t = 0 and reopened after a long time at t = t0.
(a) The charge on C just after t = 0 is εC.
(b) The charge on C long after t = 0 is εC.
(c) The current in L just before t = t0 is ε/R.
(d) The current in L long after t = t0 is ε/R.
A coil has a self-inductance of 0·05 Henry. Find the magnitude of the emf induced in it when the current flowing through it is changing at the rate of 100 As-1.
State the purpose of soft iron core used in making an electromagnet.
State the condition at which we say the two coils kept close to each other are perfectly coupled with each other.
The working of a dynamo is based on the principle of
What do moving electric charges produce?
Which group consists entirely of technologies that work on electromagnetic induction?
