a. Independent variable: <em>TIME
</em>
b. Dependent variable: <em>DISTANCE</em>
I would say your answer to this question would be D
red hot is hot, but other colours are even hotter. stars may be hotter than red hot.
there is also something calle the red shift.
Explanation:
If a metal rod of length L moves with velocity v is moving perpendicular to its length, in a magnetic field B, the induced emf is given by :

The electric field in the conductor is given by :

It is clear that the electric field is independent of the length of the rod. If the length of the rod is doubled, the electric field in the rod remains the same.