In terms of a deeper scientific reason, I am not sure, but the basic reason is quite simple. "Mud" tends to look like a mix between a solid, dirt, and a liquid, water or some other liquid. Since it is, in fact, a cross between a solid and a liquid, it has properties of both. It has certain physical and visual properties that only a solid would have, such as texture and opaqueness, but it also has physical properties of a liquid. Since it leans more towards the liquid side than the solid side, we say mud "flows" rather than saying that it "rolls" or "bounces".
Answer: Photoelectric is characterized by or involving the emission of electrons from a surface by the action of light.
Photoelectric effect is the emission of electrons when a radiation of frequency higher than the threshold frequency falls on the surface of an element. The substance which undergoes photoelectric effect is called as photoelectric.
Ground state is the state representing the lowest energy state.
Excited state is the state which represents a high energy state.
An electron in ground state absorbs energy to move to the excited state.
Answer:
a tendency to do nothing or to remain unchanged.
Explanation: