Answer:
Particle
Explanation:
To understand photoelectric effect the physicists has to view light as a particle and not wave. The wave nature of the light could not explain the phenomenon of photoelectric effect.
Photoelectric effect is emission of electrons from a material when electromagnetic radiation(Light) is incident on it. These emitted electrons are called photoelectrons.
The explain this effect Einstein proposed that beam of light is can not be a wave propagating through space, but a swarm of discrete energy packets, called as photons.
The strong nuclear force is responsible for holding nuclei together
Answer:
Since the gravitational force is directly proportional to the mass of both interacting objects, more massive objects will attract each other with a greater gravitational force. So as the mass of either object increases, the force of gravitational attraction between them also increases.
Volcanoes: Most volcanoes are formed by the movement of tectonic plates<span> on the surface of the earth. These plates basically float on mantle. Sometimes these plates will sink into the mantle. The rock becomes so hot it melts. Gradually, the molten rock (the melted rock) will then make it's way back up. When it surfaces it, we call it "lava". As lava layers, it slowly forms a volcano.
Valleys: Basically formed by a river valley. The stream shapes the Earth's crust over time into a funnel-like v-shape or u-shape (depending on the flow of the stream).
Mountains: When plates collide and through pressure start building up into a cone shape.</span>
