You are 50 km from an electric power plant. Electrons travel 10,000 meters/second through a conductor. How long does it take an electron to travel from the power plant to where you are?
In my home state of South Australia high school math is treated as a science and teachers have to be able to cover all five: math, chemistry, physics, biology and geology, at least up to tenth grade. Ergo, you do have to know the difference between alternating and direct current. DC isn't used over distances of 50km, resistance causes it to attenuate too rapidly. With AC the electrons oscillate back and forth rather than actually travelling.
Element 99 