Longitudinal, because the sound can only travel at one direction
Answer:
The observed wavelength on Earth from that hydrogen atom is 
.
Explanation:
Given that,
The actual wavelength of the hydrogen atom, 
A hydrogen atom in a galaxy moving with a speed of, 
We need to find the observed wavelength on Earth from that hydrogen atom. The speed of galaxy is given by :
is the observed wavelength
So, the observed wavelength on Earth from that hydrogen atom is . Hence, this is the required solution.
Explanation :
(1) Big bang : (1) The most accepted theory on the origin of the universe.
This theory shows the expanding of the universe from high density and high-temperature states.
(2) Steady state : (3) All is the same and will always stay the same.
Steady state means that the properties of any system remain the same always.
(3) Oscillating universe : (4) Agrees with the big bang theory but insists the universe expanded much quicker.
Oscillating universe theory is the result of big bang theory.
(4) Inflation Choices : (2) it's like an inflating and deflating balloon that never stops.
In cosmology, cosmic inflation or deflation is just the expanding and contraction of the universe.
So, the statements and the choices are related as:
(1)-(1)
(2)- (3)
(3)-(4)
(4)-(2)
I'm not sure what the alien Theory says or if there really is such a theory. If the theory says that aliens definitely exist and that they have visited Earth in the past then the theory is totally and completely without any kind of support. It's not scientific in any way because there is no evidence for such a claim. It may be thought to be probable but no solid evidence has ever been presented.
The answer is refracts parallel to the axis of the lens
