IIT JEE , AIEEE Forum - Physics , Electricity

Mr.IITIAN007

Hey guys , this is a question on magnetic effects of current . Check this out ;-

A conductor is made in the form of a hollow cylinder with inner and outer radii a and b respectively. It carries a current I uniformly distributed over its cross section. Then what is the expression for magnitude of magnetic field in the regions
i) r < a
ii) a < r < b
iii) r > b
where r is the distance from the axis.

asmit

Apply ampere law judiciously

for example in (1) i_encby cylinder loop is zero therefore from symmetry integration reduces to ba=0 or b=0

similarly try (b),but be careful abt the intg. part.

Mr.IITIAN007

Ya I know that Asmit . But I am not getting the correct expression.What expression you are getting friend if you have tried to solve it ?

asmit

(b) Applying ampere's law on a cylinder of radius x where a<x<b you get

B*2

x={(

*I)/(b^2-a^2)}*x^2 where I is the total current flowing now you can solve.For last part just put x=b.

the qty. I/(pie)(b^2-a^2) is current per unit area.Now multiply with (pie)(x^2) to get current enclosed by cylinder of radius x.

Hope you get it.

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