PV Gap

Richard Said:

How many solar panels would you need to equal the energy output of 1kg of U-235?

We Answered:

Unless the student is supposed to be able to calculate how long it takes the U-235 to produce that amount of energy, there is not enough information. If that is within the scope of the course, the question is way out of my league.

But assuming you just left out the time when stating the problem, divide that into 80 trillion to get joules/sec.

Let's say the time is 40 billion seconds* for the U-235 to generate 80 trillion J. Divide 80 trillion by 40 billion, that's 2,000 J/sec. You would need 10 panels. (A typical panel produces 200 Joules/sec.)

*That's a LOT of seconds, even a lot of centuries. By then the solar panels would have worn out and crumbled into dust, so it's a silly question in that sense. Is the teacher trying to make a point about the futility of solar power?