# #

A high-energy proton accelerator produces a proton beam with a radius of $$\textrm{mm}$$. The beam current is $$\rm\mu \rm{A}$$ and is constant. The charge density of the beam is $$n =$$ $$\times 10^{11}$$ protons per cubic meter.

## Part 1#

What is the current density of the beam?

## Part 2#

What is the drift velocity of the beam?

## Part 3#

How much time does it take for $${{params.p}} \times 10^{10}$$ protons to be emitted by the accelerator?

$$v\_{d}=$$ $$\mathrm{m}/\mathrm{s}$$
$t=$ {{ correct_answers.part3_ans_str }} $\mathrm{s}$