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**1. Homework Statement**

Consider an infinite sheet of parallel wires. The sheet lies in the xy

plane. A current I runs in the y-direction through each wire. there are

N/a wires per unit length in the x direction. Write an expression for B(d)

the magnetic field a distance d above the x y plane of the sheet and we

have to express the magnetic field as a vector.

**2. Homework Equations**

Ampere's Law --> closed integral of (Bdl) = uIencl

**3. The Attempt at a Solution**

I know that by using the right hand rule, the magnetic field would

pointing in the negative x direction if i pick a point above the surface.

Then I tried to figure out what Iencl is and I get I = (N/a)(a)(I) = NI

Then using ampere's law I get

B(top integral + bottom integral) = uNI

B(2a) = uNI

B= UNI/2a

and since the magnetic field is heading towards the negative x direction

I typed in B = -(uNI)/2a x

Please help! I don't know what I'm doing wrong! Thanks!