Light years are the distance light can travel in a full year. They are used because there are really big distances in the universe that are easier to measure with a really large form of measurement (light years).
Answer:
Speed is same as that before it entered glass.
Explanation:
Given:
A light ray enters and passes through the glass as shown in the diagram.
We have to analyze its speed.
Speed of light in air is
and speed of light in glass is
Whenever a light ray enters a glass block or slab there is bending of light at the interface of the two media.
So speed of light will decrease in glass medium and again it passes to the air.
So
Speed of light in air will again increase or will be equivalent to the earlier speed when it was entering the glass block.
Finally
Speed is same as that before it entered glass as it in the same medium (air).
The inner planets are usually rocky because the gravitational pull is stronger closer to the star or in this case the sun. The dust and rocky particles that are left over after a super nova or in a nebula will tend to orbit closer to a proto-star when a solar system is in its early days. In our solar system these planets are Mercury, Venus, Earth and Mars. Gases are less dense and will be less affected by the pull of gravity because rocky particles have more mass. The outer planets are gas giants formed from clouds of gas that would be further out in the spinning disk around a proto-star.
Answer:
16 cm
Explanation:
For protons:
Energy, E = 300 keV
radius of orbit, r1 = 16 cm
the relation for the energy and velocity is given by

So,
.... (1)
Now,

Substitute the value of v from equation (1), we get

Let the radius of the alpha particle is r2.
For proton
So,
... (2)
Where, m1 is the mass of proton, q1 is the charge of proton
For alpha particle
So,
... (3)
Where, m2 is the mass of alpha particle, q2 is the charge of alpha particle
Divide equation (2) by equation (3), we get

q1 = q
q2 = 2q
m1 = m
m2 = 4m
By substituting the values

So, r2 = r1 = 16 cm
Thus, the radius of the alpha particle is 16 cm.
The answer is it increases the amount of solar
radiation that is redirected into space. Most of the particles emitted
from volcanoes cool the earth by covering entering solar radiation. The cooling
result can last for months to years contingent on the features of the eruption.