Answer:
35.16 degrees
Explanation:
Knowing that the index of refraction of the guide is 1.33, calculate the resulting angle of refraction for a ray of light that falls on a pool with an angle of incidence of 50º
Refractive index, n = 1.33
The angle of incidence, i = 50°
We need to find the angle of refraction. let it is r. It can be calculated using Snells law as follows:

So, the angle of refraction is 35.16 degrees.
hertz: A unit for measuring frequency, equal to one cycle per second. If a sound wave has a frequency of 20,000 Hz,
Answer:
10 V
Explanation:
The potential difference between two points is the amount of work required to carry a unit charge from one point to the other point. This would result in a potential difference between this two points.
The difference between the potential across two points B and A is 
From the image attached:

I think the airplan flies in same speed 400
Types of Gas? I'm not exactly sure what you're asking