ELECTROMAGNETISM-torque on a current coil

  • Thread starter Thread starter jsalapide
  • Start date Start date
  • Tags Tags
    Coil Current
AI Thread Summary
The discussion centers on calculating the maximum torque on a circular coil with 50 turns, a radius of 0.2m, and a current of 5A in a magnetic field of 0.6 Web/m^2. The initial formula used for torque was r=NBIAcos(theta), assuming the angle for maximum torque is 0 degrees. However, clarification reveals that the angle should be defined as the angle between the area vector of the coil and the magnetic field, where maximum torque occurs at 90 degrees. The correct torque calculation involves using the formula μ X B = NIAB sin(theta). The standard unit for torque is Newton-meter, which is equivalent to web-A.
jsalapide
Messages
39
Reaction score
0
A circular coil of 50 turns has a radius of 0.2m and carries a current of 5A. The coil is in a field where the magnetic induction is 0.6 Web/m^2. What is the max torque on the coil?

I used the formula for the torque on a coil: r=NBIAcos(theta)
I assume that the angle for max torque is 0
my answer is 6pi..

is that right?
is it ok to let the angle be 0??
 
Physics news on Phys.org
Looks OK to me.

I'm not sure how you defined your angle theta. Usually it's defined as the angle between the area vector (normal to the plane of the coil) and the magnetic field, in which case the torque is given by μ X B = NIAB sin(theta). Using that definition, the torque is maximum when theta = 90 degrees.
 
Ah.. my theta is the angle between the plane of the coil and the field

anyways,, thanks..

how about the unit? Is it web-A?
 
jsalapide said:
how about the unit? Is it web-A?
The standard unit for torque is Newton-meter (which is equivalent to web-A).
 
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
Thread 'Voltmeter readings for this circuit with switches'
TL;DR Summary: I would like to know the voltmeter readings on the two resistors separately in the picture in the following cases , When one of the keys is closed When both of them are opened (Knowing that the battery has negligible internal resistance) My thoughts for the first case , one of them must be 12 volt while the other is 0 The second case we'll I think both voltmeter readings should be 12 volt since they are both parallel to the battery and they involve the key within what the...
Back
Top