Magnetic flux through the circular cross-sectional area of the solenoid

[Kourtney0115]

Homework Statement

A solenoid 1.7 cm in diameter and 30 cm in length has 4000 turns and carries a current of 5 A. Calculate the magnetic flux(in Wb) through the circular cross-sectional area of the solenoid. Since this is a very long solenoid, you may use the simplified magnetic field formula for the infinite solenoid.

Homework Equations

B = µ * N * I

The Attempt at a Solution

B = (4 . π . 10^–7) . (4000 / 0.3) . 5 = 8.4 . 10^–2 T


My online homework is telling me this is incorrect. I am not sure what I am doing wrong.

 

[collinsmark]

Hello Kourtney0115,

It seems you've already calculated the magnetic field (measured in Teslas). Next step is to find the magnetic flux (measured in Webers).

 

[Kourtney0115]

Im not sure how to convert T into Wb. I tried to look it up on google and the only thing i found was T=Wb/m^2. But i am not given m^2.

 

[collinsmark]

Im not sure how to convert T into Wb. I tried to look it up on google and the only thing i found was T=Wb/m^2. But i am not given m^2.

Magnetic flux is the magnetic field integrated over some surface (which has an area). For the special case where magnetic field is constant over a given area (surface), the the magnetic flux through that surface is the dot product of the magnetic field and the surface (the "surface" being something which has a surface area).

Hint: The problem statement says, "...through the circular cross-sectional area of the solenoid."