Aproton beam in an accelerator carries a current of 106 μa. if the beam is incident on a target, how many protons strike the target in a period of 17.0 s?

The electric current is defined as the charge Q that passes a certain point in a time :

We know the current, , and the time, , so the total charge that strikes the target during this time is


To find the number of proton, we must divide the total charge by the charge of a single proton, which is :

And this is the number of protons that strike the target in 17.0 s.