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EMI – A Rectangular loop entering a uniform magnetic field.

I have one question friends –
If a rectangular loop is entering a perpendicular magnetic field then using Fleming right hand rule how will you explain the direction of induced current in the loop.
Pl explain how

WhatsApp Image 2016-08-05 at 4.02.25 PM(Mr. Nath posted)

 

Answer

Initially an emf will be developed across AD from D to A according to Fleming’s Right Hand Rule.

When the loop is completely inside the magnetic field, the emf across AD will be same as the emf across BC. Therefore, though CD is at a higher potential and AB is at a lower potential, no net current flows since the two emfs oppose each other equally.

(Vivekananda Sir said: Loop is moving inside the field so induced current will be in the direction DABCB.)

 

Doubts from Faraday’s Experiments on electromagnetic induction

I wanna ask that in faradays’s first experiment with coil and magnet,when the magnet is moved away from coil the deflection in galvanometer becomes opposite as compared to first case…..what leads to this and if that means direction of current becomes opposite so HOW and WHY the direction of this changes…..plz can you tell me the practical reason of this…..its really confusing me!!!

Asked Arti

Answer will be posted soon

(Visitors are welcome to post their response via comments)

Working of a microphone

How does a microphone do its work? Please explain me and can you give me answer in language Hindi I’m very thankful to you. (Shubham Agnihotri asked)

Answer:
inside a microphone
Microphone is a transducer (a device which converts energy from one form to another). The microphone converts sound energy to mechanical energy and then to electrical energy.

When we speak into the mic, the vibrations of the air produced by the sound make the diaphragm of the mic vibrate. A coil attached to the diaphragm vibrates together with it. The coil is moving in a strong magnetic field produced by a permanent magnet. Whenever the magnetic flux linked with coil changes an emf is induced in it. Therefor when we speak into the mic, an emf varying similar to the pressure variations produced by our sound is produced across the coil by electromagnetic induction.

If the ends of the coil is connected to an amplifier this can be amplified and can be send to the loudspeaker. The working of the loudspeaker is just the reverse of that of the microphone. I converts the electrical signal to sound signals.

(Please use Google Translate  or Click Here to get the Hindi Version)

Electromagnetic induction in outer space and energy conservation

“lets pretend we are in space. and there  I have a permanent magnet rotor that and around it are copper windings. They do not touch and everything is floating with minimum friction (because we are in space)
imagine a generator with no brushes or bearings….

now my question is :
if i spin the rotor, and electrons start flowing on the copper(electricity)
would there be a negative force on the rotor to make it stop faster ?

Thank you

(Posted by )

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