Explanation:
Rutherford proposed a revised model for the atom, called the planetary model. The previous model of the atom was Thomson's Plum Pudding Model which consisted of freely moving positive and negative charges inside the atom.
Rutherford proposed his model after an experiment he conducted called the Gold Foil Experiment. This experiment consisted of a thin gold sheet into which alpha particles were shot upon and they were detected by a sensor. The image attached will give a better explanation of this. In this experiment he shot a beam of alpha particles(helium nucleus) at a thin sheet of gold. Rutherford hypothesised that there should be minimum deflection of the positively charged alpha particles occuring due to the repulsion of the alpha particle with the positive charges in the thin gold sheet. This was not the case.
However what he found was that most of alpha particles went straight through the thin sheet of gold but some were reflected back to him. This surprised him. Hence he proposed that most of the atom must be empty space as most of the alpha particles went straight through the sheet and there must be a heavy nucleus inside the atom causing the alpha particles to bounce back.
Answer and Explanation:
In optics, a CoC(Circle of Confusion) is defined the minimum cross section of a paraxial bundle of rays made by a lens which is sphero-cylindrical type and can be viewed as an optical spot, which do not converge perfectly at the focus while a point source is being imaged due to spherical aberration.
The Circle of Confusion is also referred to as circle of indistinctness or a blur spot
Answer:
3 m/s
Explanation:
First, find the time it takes to land.
Given in the y direction:
Δy = 0.8 m
v₀ = 0 m/s
a = 10 m/s²
Find: t
Δy = v₀ t + ½ at²
0.8 m = (0 m/s) t + ½ (10 m/s²) t²
t = 0.4 s
Next, find the velocity needed to travel 1.2 m in that time.
Given in the x direction:
Δx = 1.2 m
a = 0 m/s²
t = 0.4 s
Find: v₀
Δx = v₀ t + ½ at²
1.2 m = v₀ (0.4 s) + ½ (0 m/s²) (0.4 s)²
v₀ = 3 m/s
Answer:
Explanation:
A.
Given:
Vo = 21 m/s
Vf = 0 m/s
Using equation of Motion,
Vf^2 = Vo^2 - 2aS
S = (21^2)/2 × 9.8
= 22.5 m.
B.
Given:
S = 22.5 + 21 mm
= 22.521 m
Vo = 0 m/s
Using the equation of motion,
S = Vo × t + 1/2 × a × t^2
22.521 = 0 + 1/2 × 9.8 × t^2
t^2 = (2 × 22.521)/9.8
= 4.6
t = 2.14 s
Answer:
A. the satellite cools off by radiation.
Explanation:
First of all, let's define the three methods of heat transfer:
- Conduction: conduction occurs when two objects (or two substances) are in contact with each other - the heat is transferred by the warmer object to the colder object by collisions between the particles of the two objects
- Convection: convection occurs when a fluid is heated by an external source of heat - the heat transferred by the source produce a movement of the particles in the fluid (the warmer part becomes less dense and rises, being replaced by the colder part of fluid which sinks, producing a convective current)
- Radiation: radiation occurs when an object emits electromagnetic radiation, which carries energy and heat. Every object emits electromagnetic radiation, so every object emits heat by radiation.
While the first two methods (conduction and convection) occur only if there is a medium involved, radiation can also occur in a vacuum, so also in empty space. Therefore, the satellite in space cools off only by radiation, since conduction and convection are not possible.