IIT JEE , AIEEE Forum - Physics , Magnetism

trisha

The magnetic fields on both sides of an infinite current carrying surface are given by B₁and B₂ respectively.Find the pressure on the surface.(here i mean B₁& B₂ in vectorial notation.i.e.,B₁bar and B₂bar)

neeleshv

What do you mean by pressure. On what if it is wire we need the surface area of the wire

001sri

let us consider the sheet to b carrying a current in +ve z direction and lying along z-y plane with current per unit length(along y axis be W.L b the length of sheet along z axis. then
F =B1wdyL-BWdyL
P=(B1-B2)w

so whats the ans.
rate me if i m correct.

001sri

here B! and B2 must b parell to the sheet.
i had used F=BiL

krishna.gopal

Consider the sheet to be lying in yz plane and current is flowing along +z axis. The net field in the neighourhood of sheet will be have field because of sheet Bs and field because of other factors Bo. On one side of sheet field will be Bo+Bs and on other it will be Bo-Bs (Direction of Bs will be opposite on both sides)
Putting Bo+Bs = B1
and Bo-Bs= B2
Bo=(B1+B2)/2 (Here additions are vector additions)
Bs = mu*J/2 (where J is currect density)=(B1-B2)/2

Now consider a unit thin sheet of length l and width w.

It carries a current Jw and hence force on that piece is
F=iBl=JBo*lw
so pressure is JBo=(1/2mu)*(B1-B2)*(B+B2)

trisha

thank u sir

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