Nerve cells transmit electric signals through their long tubular axons. These signals propagate due to a sudden rush of Na${^+}$ ions, each with charge $+e$, into the axon. Measurements have revealed that typically about 5.6 $\times$ 10$^{11}$ Na${^+}$ ions enter each meter of the axon during a time of 10 ms. What is the current during this inflow of charge in a meter of axon?