Answer:
D.None of these
Explanation:
The derivation of acceleration formula:
Let us call the 5kg mass
and the 4kg mass
. If the tension in the string is
then for the mass 
(1).
<em>(the negative sign on the right side indicates that acceleration is downwards)</em>
And for the mass 
(2).
<em> (the acceleration is upwards, hence the positive sign)</em>
Solving for
in the 2nd equation we get:
,
and putting this into the 1st equation we get:


Back to the question:
Using the formula for the acceleration we find


which is the acceleration that none of the given choices offer. Also, the acceleration of the two blocks is the same, because if it weren't, the difference in the instantaneous velocities of the objects would cause the string to break. Therefore, these two reasons make us decide that none of the choices are correct.
Answer:
Red light
Explanation:
The energy emitted during an electron transition in an atom of hydrogen is given by

where
is the energy of the lowest level
n1 and n2 are the numbers corresponding to the two levels
Here we have
n1 = 3
n2 = 2
So the energy of the emitted photon is

Converting into Joules,

And now we can find the wavelength of the emitted photon by using the equation

where h is the Planck constant and c is the speed of light. Solving for
,

And this wavelength corresponds to red light.
Answer:
the answer is UV Radiation
I think comets because they are small and they are composed of ice or water. Hope it helps :)