Consider an infinetly long hollow cylindrical wire. The wire has an outer diameter b and the clindrical hole at its center has diameter a. Find the magnetic field everywhere if a known current i flows from left to right and the current is uniformly spread over the region between a and b.

B = (μ₀*i/(2*π*x))*(x²-(a/2)²)/((b/2)²-(a/2)²)

Explanation:

Given

Outer diameter of the wire = b  ⇒ R = b/2

Diameter of the clindrical hole at the center = a  ⇒ r = a/2

The current that flows from left to right and is uniformly spread over the region between a and b = i

We apply Ampere's Law

Using the following formula for  a/2 ≤ x ≤ b/2

B = (μ₀*i/(2*π*x))*(x²-(a/2)²)/((b/2)²-(a/2)²)

when jerome paddle in flowing river towards east the net speed of jerome will increase

so the net speed of jerome will be given as

now the speed of paul will be same as it is given as he is running on the ground

so

so here we can say since the speed of jerome is more so he will win the race

now as we know the distance so the time difference is given as

so jerome will reach first and the time difference will be 203.55 s or 3.4 min

0.93xc=0.93x3x10^8m/s

2.54cm is 1 inch

360seconds i 1 hr