Answer: Albert Einstein
Explanation:
Light can be considered as a wave or as particles, in this context Einstein proposed that light behaves like a stream of particles called <u>photons</u> with an energy, in order to correctly explain the photoelectric effect (in fact he won the 1921 Nobel Prize in Physics because of this explanation).
To uderstand it better:
The photoelectric effect is a fenomenom that consists in the emission of electrons that occurs when light falls on a metal surface under certain conditions.
This can only be explained based on the corpuscular model of light, that is, light is quantized.
So, Einstein theorized light as a stream of energy packets called photons, this energy is able to pull an electron out of the crystalline lattice of the metal and communicate, in addition, a kinetic energy.
Actually a black board has all colours in light or white light . So when light falls on it board absorbs all colours because all are present so no light is reflected back. That is the case, and so it will appear black as it absorbs all colours of light that fall on it .
Answer:
T = mg - 
×V×g
Explanation:
Here we have the mass of the ball is given as 
The density of the fluid =
The volume of the ball = V
Acceleration due to gravity = g
According to Archimedes's principle, the upthrust = Weight of fluid displaced
Tension in string = T = weight of ball - upthrust
T = mg - ×V×g
The electrical charge is neutral. I hope this helps!
