Answer:
b) the refracted ray has an angle of 90 degrees
Explanation:
The angle of incidence is measured with respect to the normal separation of the media. The critical angle for total internal reflection occurs is:

Here
and
are the refractive index of the mediums. This equation is an application of Snell's law, for the case where the refracted ray has an angle of
.
Answer:
Grow plants where little light is available
Explanation:
The plants need the ultraviolet rays in order to be able to survive and develop. The need mainly comes from the dependence of these rays for production of food, in a process known as photosynthesis. The plants are producers, thus they create their own food. In order to be able to do that they are using the ultraviolet rays, as well as water, and carbon dioxide. By combining them, the plants manage to create glucose for them, and that is their food source. The plants that are kept at places where there's not enough light are often exposed to ultraviolet rays so that they are able to perform the process of photosynthesis and grow properly.
Complete Question
Q. Two go-carts, A and B, race each other around a 1.0km track. Go-cart A travels at a constant speed of 20m/s. Go-cart B accelerates uniformly from rest at a rate of 0.333m/s^2. Which go-cart wins the race and by how much time?
Answer:
Go-cart A is faster
Explanation:
From the question we are told that
The length of the track is 
The speed of A is 
The uniform acceleration of B is 
Generally the time taken by go-cart A is mathematically represented as
=> 
=> 
Generally from kinematic equation we can evaluate the time taken by go-cart B as

given that go-cart B starts from rest u = 0 m/s
So

=>
=>
Comparing
we see that
is smaller so go-cart A is faster
<span>The charged balloon will stick to a neutral wall because of the Static Electricity:
</span>
The matter is formed by atoms and these atoms are composed of electrons, protons and neutrons (the electrons have a negative charge, the protons have a positive charge and the neutrons have no charge).
As the balloon is charged (It gained electrons), and the charge of the same sign repel each other, when it approaches the wall, the electrons of this wall will move away, and the positive charges (protons) will remain in the nearest area to the balloon. As the charges of different signs are attracted, the balloon will be stuck to the wall.