Q:

Current in the loop with two protons

Let there be a circular loop of radius r and two protons are moving in this loop with same (and constant speed $v$). They are always  at diametrically opposite ends. They complete one revolution about the centre in time $t$ [which is $2\pi r/v$]
Now the question is, what is the current flowing in the loop?
I have two possible answers: $ i=q/t $ as $q $ charge is flowing through a cross section of loop  and $ i=2q/t$ if $i$ is net charge/time where $q $ is charge on one proton. I think the first one is better but I can't say for sure. Kindly help me out .

A:

In this case $I=2q/t$. Consider any fixed point on the loop. Over any $t$ the charge passing that point is $2q$

