How do collisions between molecules transfer energy from a system of reacting substances to its surroundings?
A. They cause molecules to flow into the system from the
surroundings.
B. They cause heat to flow from the system to the surroundings.
C. They cause the thermal energy of the surroundings to decrease.
D. They cause the potential energy of the system to increase.

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