PLEASE HELP !!! Which statement correctly describes protons?
A.
They have no charge and are present in the nucleus of an atom.
B.
They have a negative charge and travel around the nucleus of an atom.
C.
They have a positive charge and travel around the nucleus of an atom.
D.
They have a positive charge and are present in the nucleus of an atom along with the neutrons.

Which transition by an electron will release the greatest amount of energy? oa ob oc od

Asheet of steel 1.5 mm thick has nitrogen atmospheres on both sides at 1200oc and is permitted to achieve a steady-state diffusion condition. the diffusion coefficient for nitrogen in steel at this temperature is 6 x 10- 11 m2 /s, and the diffusion flux is found to be 1.2 x 10-7 kg/m2 -s. also, it is known that the concentration of nitrogen in the steel at the high-pressure surface is 4 kg/m3 . how far into the sheet from this high-pressure side will the concentration be 2.0 kg/m3 ? assume a linear concentration profile.

Two positive charges are equal. which has more electric potential energy?