Torque on a charged particle moving in a circle in a uniform B field

Click For Summary
The discussion focuses on calculating the maximum torque exerted on a charged particle moving in a circular path within a uniform magnetic field. The particle, with charge q = e, moves at a speed of 2.350×10^7 m/s and has a radius of 0.44 m. The participant successfully calculates the mass of the particle but struggles to connect this information to the torque experienced by a current loop in a magnetic field. It is emphasized that the magnetic field causing the circular motion is not the same as the uniform field being analyzed for torque. The participant is advised to consider the average current of the moving charge and to research the relationship between torque and magnetic moments in current loops.
ganondorf29
Messages
49
Reaction score
0

Homework Statement



A particle of charge q = e moves in a circle of radius = 0.44 m with speed v = 2.350×107 m/s. Treating the circular path as a current loop with constant current equal to its average current, find the maximum torque exerted on the loop by a uniform magnetic field of magnitude B = 1.00 T.

Homework Equations



R=mv/qB

The Attempt at a Solution



I'm stuck and I don't really know where to go. I did find the mass by the following equation:
m = rqB / v
m = 0.44 * 1.602E-19 * 1 / 2.35E7
m = 2.999E-27 kg

I could also find KE but I'm not sure what to do with either of these two. How does torque relate to magnetism?
 
Physics news on Phys.org
ganondorf29 said:
I'm stuck and I don't really know where to go. I did find the mass by the following equation:
m = rqB / v
m = 0.44 * 1.602E-19 * 1 / 2.35E7
m = 2.999E-27 kg
You are solving a different problem. Realize that the given magnetic field is not the field that is making the charge go in a circle.

Treat the moving charge as a current loop. (What's the average current?) A current loop placed in a magnetic field will experience a torque. Look up: torque on a current loop, magnetic moment of a current loop.
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

Similar threads

Replies
4
Views
2K
  • · Replies 1 ·
Replies
1
Views
825
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 8 ·
Replies
8
Views
2K
Replies
4
Views
1K
Replies
7
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
Replies
2
Views
1K