Answer:
The total time is
.
Explanation:
Given:
The distance between Galactic Capitol and Earth is, 
The speed of light is, 
The time taken by the message to reach and come back to Earth is given by

In addition they take 1 year to decide to reply.
Thus, the total time is
.
As the wave length increases the energy of the wave decreases as the equation that relates the c=λυ λ is the wave length and υ is the frequency (which is directly proportional to the energy).
In the wave length spectrum, x-ray has a shorter wave length, meaning that
x-ray has a higher energy than ultraviolet waves.
Hope this helps.
Answer:
The engine would be warm to touch, and the exhaust gases would be at ambient temperature. The engine would not vibrate nor make any noise. None of the fuel entering the engine would go unused.
Explanation:
In this ideal engine, none of these events would happen due to the nature of the efficiency.
We can define efficiency as the ratio between the used energy and the potential generable energy in the fuel.
n=W, total/(E, available).
However, in real engines the energy generated in the combustion of the fuel transforms into heat (which heates the exhost gases, and the engine therefore transfering some of this heat to the environment). Also, there are some mechanical energy loss due to vibrations and sound, which are also energy that comes from the fuel combustion.