Question

Given J, find I. (Attached)

Answer 1

PLease help!

Answer 2

I know this:
\[I=\int\limits_{S}^{}Jds\]

Answer 3

@ParthKohli

Answer 4

@ash2326
@UnkleRhaukus
@robtobey

Answer 5

I got 50pi but the answer says 100pi

Answer 6

It seems to be just an integral we have to plug ds=r
dr dtheta

Answer 7

\[\int\limits_{0}^{5}\int\limits_{0}^{2\pi}J r dr d \Theta \]

Answer 8

What shape is that surface? Is it a sphere?

Answer 9

If it's a sphere, then your integral should be
\[ \int J R^2\sin(\theta) d\theta d\phi= 4 \pi R^2 J = 4\pi R \cdot 5 = 100\pi\]

Answer 10

there's no actual integration required. The magnitude of the current density is constant, and everywhere perpendicular to the surface of the sphere so you just need to multiply J by the surface area of the sphere, 4 pi R^2