During the collision between two balls on the pool table there is no external force along the line of collision between them
Since there is no external force on it so here we can say

here we have

so we can say

since there is no external force so we can say during the collision the momentum of two balls will remain conserved
The reason why there is no energy shortage nor will there ever be is because energy is being preserved and conserved and only changes form. It never gets lost or increased.
Answer:
the kinetic energy is less after a substance changes from liquid to gas
Explanation:
the kinetic energy is greater after a substance changes from a solid to liquid
Answer:
B) Within an atom, an electron can have only particular energies.
Explanation:
As we know that electrons have energy but apart from electrons we know that protons and neutrons inside the nucleus of atom will also have energy in them.
rest all the statements are true as we have
A) Electrons orbit the nucleus rather like planets orbiting the Sun.
TRUE, because electrons can move in stationary orbit around the nucleus
C) Electrons can jump between energy levels in an atom only if they receive or give up an amount of energy equal to the difference in energy between the energy levels.
Difference amount of energy is lost or absorbed by the electron in form of photons
D) An electron has a negative electrical charge.
Charge of an electron is given as 
E) Electrons have very little mass compared to protons or neutrons
Mass of an electron is given as

mass of proton or neutron

The answer is Eficiency=T<< Tox100