The concept of power is given by the relationship between intensity and area, that is to say that power is defined as
Our values are given under the condition of,
The power is proportional to the Area, and in turn, we know that the Area of a circle is the product between 
times the radius squared, therefore the power is proportional to the radius squared.
For both panels we would have to
Therefore the correct option is option C.9
Answer:
Please see answer in explanation
Explanation:
1. Since each molecule has three kinetic degrees of freedom (can move in three independent directions), the gas must have 3N DoFs.
2. Each molecule has the three kinetic degrees of freedom the monotonic atom has moving without rotating but it can also spin. There are three axes for it to spin around so we would expect three rotational degrees of freedom, but as were as above, the one about the diatomic molecule's axis doesn't count because of quantum. So we have two rotational DoFs and three kinetic, for a total of 5 per molecules. So the gas will have 5N DoFs.
3.When a spring vibrates it has two DoFs, its KE and its PE, so adding 1 vibration adds 2 DoFs per molecule, giving 7 per molecule and giving thegas 7N DoFs.
