D. About 25%
25% of stars have compainions
Answer:
Percentage of mass converted to energy = 99.9 %
Explanation:
By far most of the solar system's mass is in the Sun itself: somewhere between 99.8 and 99.9 percent. The rest is split between the planets and their satellites, and the comets and asteroids and the dust and gas surrounding our star. Seen from afar (on the scale of distances between stars) the presence of the solar system would not be obvious. We would simply see a normal-looking star. Perhaps we would pick up the presence of Jupiter, which makes up two thirds or so of the solar system outside of the Sun, by mass.
The answer to this question to A. The other choices are positive.
To solve this problem we need the concepts of Energy fluency and Intensity from chemical elements.
The energy fluency is given by the equation

Where
The energy fluency
c = Activity of the source
r = distance
E = electric field
In the other hand we have the equation for current in materials, which is given by

Then replacing our values we have that


We can conclude in this part that 1.3*10^7Bq is the activity coming out of the cylinder.
Now the energy fluency would be,



The uncollided flux density at the outer surface of the tank nearest the source is 
Answer:
Time, I believe. Pretty sure it's time lol