# Does it matter how many turns it makes for dingint he moment and torque?

1. Nov 2, 2005

### mr_coffee

Hello everyone 'im confused...all these problems keep bringing up how many times a coil turns, and yet the forumla/book doesn't apply the case if its turning or spinning. FOr example, this problem asks:
A circular coil of 200 turns has a radius of 2.10 cm.

(a) Calculate the current that results in a magnetic dipole moment of 2.30 Am2.
A
(b) Find the maximum torque that the coil, carrying this current, can experience in a uniform 40.0 mT magnetic field.
Nm

I know the equation:
M = AI;
Would i use the area of a circle because its a coil? and why does it tell me it turns 200 times, is it goign to effect the area or current or what?> Also to find the maximum torque, can i use the equation of:
T = IAB? where B is the magnetic field, and A is the area nad I is the current?

2. Nov 2, 2005

### mathmike

it isnt turning 200 times, it means that the wire is wrapped around the core 200 times, or there is 200 layers of wire around the core.

3. Nov 2, 2005

### mr_coffee

How does that effect the area or current?

4. Nov 2, 2005

n/m i got it