The temperature of a substance is

a
equal to the kinetic energy of the fastest moving molecule in the substance.
b
proportional to the average kinetic energy of the molecules in a substance.
c
proportional to the lowest kinetic energy available to a molecule.
d
proportional to the average momentum of the fastest 50% of the molecules in the substance.

The electric field between square plates of a parallel-plate capacitor has magnitude e. the potential across the plates is maintained with constant voltage by a battery as they are pulled apart to twice their original separation, which is small compared to the dimensions of the plates. the magnitude of the electric field between the plates is now equal to a)e b)e/4 c)e/2 d)4e e)2e