I am quite sure the first one is Friction, but I am not sure about the second one. Is it wind?
Answer: choices a and b
Explanation:
Telescope can be defined as am optical instrument which is designed to observe the distant objects clear and nearer. It comprises of arrangement of lenses which allow the rays of light to be collected. The collected light is focused and the image so produced is magnified in the form of an image. The telescopes are prepared and manufactured on mountains top as this will help in preventing the distortion of light obtain from the star due to the fluctuation of air mass in the atmosphere. The atmospheric distortion affects the resolution, and affects the vision. The atmospheric pressure is low at the mountain tops so it will help in better observation of the sky.
Answer:
Please refer to the figure.
Explanation:
The crucial point here is to calculate the enclosed current. If the current I is flowing through the whole cross-sectional area of the wire, the current density is

The current density is constant for different parts of the wire. This idea is similar to that of the density of a glass of water is equal to the density of a whole bucket of water.
So,

This enclosed current is now to be used in Ampere’s Law.

Here,
represents the circular path of radius r. So we can replace the integral with the circumference of the path,
.
As a result, the magnetic field is

Answer:
a) 
For this case we know the following values:




So then if we replace we got:

b) 
With 
And replacing we have:

And then the scattered wavelength is given by:

And the energy of the scattered photon is given by:

c) 
Explanation
Part a
For this case we can use the Compton shift equation given by:
For this case we know the following values:
So then if we replace we got:
Part b
For this cas we can calculate the wavelength of the phton with this formula:
With
And replacing we have:
And then the scattered wavelength is given by:
And the energy of the scattered photon is given by:
Part c
For this case we know that all the neergy lost by the photon neds to go into the recoiling electron so then we have this: