Answer:
it would take rod B twice as much time
Explanation:
it would take rod B twice as much time as it is twice as thick and twice as long. Due to this reason it would take the electric charge not only more time but even more voltage to travel through the rod
The power delivered is equal to the product between the voltage V and the current I:

This power is delivered for a total time of

, so the total energy delivered to the battery is
I included things
Hope this helps!
Well, first of all, I don't think "After the collapse of a nebular cloud ..."
is the first time that "atoms begin gravitating together". Seems to me like
that's what was going on all the time, and it's what caused the nebular cloud
to collapse in the first place.
In any case, once the pressure and temperature at the center get high enough,
you get "ignition" of nuclear fusion, and that's when you first have a "star".