Isaac Physics Part E Microscopic Current question

https://isaacphysics.org/questions/microscopic_current?stage=all
Above is the URL for the Microscopic Current Question.
I'm sure Part E is a simple question but for some reason, even though I used the current density I worked out in Part D (2580960), the question says I am incorrect.
I'm using the formula for current density and rearranging it from : J = I/A to : I = JA. Am I doing something wrong?
The answer I keep getting is 8.1(2sf).
The J and A (Cross section) I'm using is:
J = 2580960 Am^-2
A = 1/100000 x pi

Reply 1

mosaurlodon

I think your answer for J is wrong - I got 2,642,690...Am^-2
im also pretty sure you have a typo for A? it should be pi x10^-6, but using your answer of pi x10^-5 wouldnt get 8.1, so I think you do have the right A?

it should be J = n*v*e, where n is part a answer, v is part c answer, and e = 1.6x10^-19

I think your problem is you're rounding some of the values - dont, just store them in your calc and I think you should be fine.