Answer:
A battery produces _DC_ current, which is current that flows in only one direction.
Answer:
c) Water molecules melt into gas molecules.
Answer:
Zero; no force is required to keep it going
Explanation:
Since the cannon ball is fired into frictionless space, there will be nothing to stop it, so it will keep going and going.
Wavelength = c/f.
Wavelength =0.5km