It is called phosphorescent substances.
The answer to the question is b
Answer:
Gravitational force is directly promotional to the mass
of both interacting objects.
Explanation:
More massive objects will attract each other with
a greater gravitional force. So as the mass of the
either objects increases the force of gravitational
attraction between them also increases.
To determine the number of potassium laid side by side by a given distance, we simply divide the total distance to the diameter of each atom. The diameter is twice the radius of the atom. We calculate as follows:
number of atoms = 4770 / 231x10^-12 = 2.06x10^13 atoms
