Heating gas to create plasma can yield a) neutrons. b) elements. c) molecules. d) free electrons.

Plasma is known as the 4th state of matter and is itself ionized gas. In this sense, ionization consists of the production of ions, which are electrically charged atoms or molecules due to the excess or lack of electrons with respect to a neutral atom or molecule.

That is why in this process there are always free electrons. Therefore in heating gas to create plasma can yield  free electrons, and the correct option is D.

pe = weightxheight = 2000x1000=2,000,000joules

current and voltage can both be different in different parts of a circuit so it matters where you place the ammeter and voltmete