# Homework Help: Finding magnetic flux-it's all worked, just have one question

1. Oct 5, 2008

### crh

Finding magnetic flux--it's all worked, just have one question

1. The problem statement, all variables and given/known data

A 15-cm-diameter circular loop of wire is placed in a 0.60-T magnetic field.
Enter scientific notation as 1.23E4.

When the plane of the loop is perpendicular to the field lines, what is the magnetic flux through the loop?

The plane of the loop is rotated until it makes a 36° angle with the field lines. What is the angle in Eq. 21-1 in your textbook, , for this situation?

What is the magnetic flux through the loop at this angle?

2. Relevant equations

$$\phi$$B=BA=B]$$\pi$$r2

$$\phi$$B=BAcos$$\theta$$=B$$\pi$$r2

3. The attempt at a solution

a. (.60T)*$$\pi$$*0.075m2=1.1E-2Wb

b. $$\theta$$=55 degrees

c. (0.60T)*$$\pi$$*0.075m2*cos55 degrees

I can get the 1st two questions correct, I know because it is online homework, but I can't get "c" right. It has been a while since I have had math with trig functions so I can't remember exactly how to calculate cosine. Can someone help me out.

2. Oct 5, 2008

### marcusl

Re: Finding magnetic flux--it's all worked, just have one question

Do it with a calculator; cos(55 deg) = 0.5736.