A long, solid, copper rod has a circular cross-section of diameter 10.0 cm. The rod has a current of 5.0 A, uniformly distributed across its cross-section. Calculate the magnetic field strength at:
a) the centre of the rod
b) 2.5 cm from the centre
c) 5.0 cm from the centre
d) 7.5 cm from the centre
This is supposed to be done somehow using B = μ/2∏ * I/r
I don't have any calculus knowledge.
The Attempt at a Solution
I've tried many ways, but nothing has been consistent. I assume that I need to figure out the value of I at each different point of the copper rod, which I've tried doing through all this finicky work with area and all this stuff, but I truly don't understand what I'm doing.