An electric current must always move in a circle or path:

• from the electric source through a wire to a uses electrical energy
• from the machine through another wire back to the
the circle, or path, must be (no gap) for electricity to flow through the wires.

(i know it's not physics, i'm in middle school but i didn't want to waste my time having to provide my parent's email address. i just need with this question.)

Select light for the type of wave, adjust the wavelength so that the light is red, and increase the amplitude of the light to the max. then, select the start button at the source location to begin producing the waves. light is a form of electromagnetic wave, containing oscillating electric and magnetic fields. the wave amplitude detector mentioned above shows how the electric field oscillates in time at the location of the probe. the amplitude of the wave at the location of the probe is equal to the maximum electric field measured. how does the amplitude of the wave depend on the distance from the source?