# Homework Help: Magnetic Flux in a Solenoid

1. Oct 10, 2015

### DaveTan

1. The problem statement, all variables and given/known data
A single-turn square loop of side L is centered on the axis of a long solenoid. In addition, the plane of the square loop is perpendicular to the axis of the solenoid. The solenoid has 1280 turns per meter and a diameter of 5.85 cm , and carries a current of 2.15 A .

Find the magnetic flux through the loop when L= 5.85 cm .

2. Relevant equations
Magnetic Field = 4pi *10^-7 * (Num loops/ length) * current
Magnetic Flux = Magnetic Field * Area * cos(theta)

3. The attempt at a solution
Magnetic Field = 4pi *10^-7 * (1280 loops/ 1.00m) * 2.15A = 0.003458T
Magnetic Flux = B * area = 0.003458 * 0.0585 * 0.0585 = 1.18x10-5

The answer is wrong, I would appreciate any help! Thanks!

2. Oct 10, 2015

### Daeho Ro

Why are you put the length as $1.00m$?

3. Oct 10, 2015

### DaveTan

Because the question says 1280 turns per meter

4. Oct 10, 2015

### Daeho Ro

Here the area is maybe the area of solenoid, isn't it?

5. Oct 10, 2015

### DaveTan

You are right! Thanks