# Homework Help: What is the magnitude of the torque exerted on the loop?

1. Oct 5, 2009

A rectangular loop consists of 101 closely wrapped turns of wire and has dimnesions .97m by .23m. The loop is hinged along the y-axis and its plane makes an angle of 70 degrees with the x axis.

A uniform magnetic field of .62 T is directed along the x-axis and the current in the loop is 3.1 A in the downward direction.

What is the magnitude of the torque exerted on the loop?

okay so for this problem I tried to apply the T=NIABsin() but that doesnt work....how do I go about this problem?

I can get the area by multiplying the dimensions
I have the current, I = 40 A
The Mag Field B=4.07 T
and 33 degrees

what do I do ?

2. Oct 5, 2009

### rl.bhat

Re: Magnetism

Values given by you do not match with the given problem. In the problem the rectangular loop is given. From where did you get the radius?

3. Oct 5, 2009

Re: Magnetism

oh sorry! that was not part of the problem. There is no radius given

4. Oct 5, 2009

### rl.bhat

Re: Magnetism

5. Oct 5, 2009

Re: Magnetism

okay so what I inititally did was T=NIABsin()

so I assumed there was only one loop so I plugged in T= (1)(3.1A)(.97*.23)sin(70)

and I got T=.4029385043

but that is not correct so what am I doing wrong? Am I just using the totally wrong equation? What am I missing?

6. Oct 5, 2009

### rl.bhat

Re: Magnetism

You didn't multiply the number of turns in the coil.

7. Oct 5, 2009

Re: Magnetism

why would I multiply the number of turns in the coil?

Also, I did that but I still did not get the right answer.

(101)(3.1 A)(.2231m^2)(.62T)sin(70)= 40.6967 N*m

8. Oct 5, 2009