PHYA5 ~ 20th June 2013 ~ A2 Physics

de Broglie one .... 4 marker. I thought it was pretty sneaky

did anyone convert the eV into V by multiply eV by e

then multiplying it by e again to get eV

I thought it was sneaky as hell

de Broglie one .... 4 marker. I thought it was pretty sneaky

did anyone convert the eV into V by multiply eV by e

then multiplying it by e again to get eV

I thought it was sneaky as hell

You did? Didn't the question say it was known to be 0.50m and you had to show it?

I only multiplied it by e once because an electron volt is voltage, so you multiply it by charge to get energy

Yeah same i got 2.5x10-19, but i didnt write that done cos i thought it was wrong i still wrote the method out, will i get a few marks?

Hmmm not sure

But e x V would give you energy

but they gave you eV... it looks like they've given you kinetic energy already which was so misleading

was a 4 marker, that's the one I didn't have a good feeling about

The formation of Helium gives off much more energy per nucleon than a normal fission. It's just over 7MeV per nucleon and there are 4 nucleons so that's 20-something MeV

What was the answer for mass at -50degrees.

I agree that that's around the answer for the question, but you're still missing the point fission reactions produce more energy than fusion reactions. I understand that there is a greater change in binding energy, and hence more energy released PER NUCLEON, but since there are so many more nucleons in fission, it outputs more energy. Even though the change in binding energy is only around 1Mev per nucleon, there are around 200 nucleons involved, so it's much more

http://en.wikipedia.org/wiki/Nuclear_fission#Output

says that it's 200MeV

this isn't even the question so it doesn't really matter

I agree that that's around the answer for the question, but you're still missing the point fission reactions produce more energy than fusion reactions. I understand that there is a greater change in binding energy, and hence more energy released PER NUCLEON, but since there are so many more nucleons in fission, it outputs more energy. Even though the change in binding energy is only around 1Mev per nucleon, there are around 200 nucleons involved, so it's much more

http://en.wikipedia.org/wiki/Nuclear_fission#Output

says that it's 200MeV

this isn't even the question so it doesn't really matter

What section is this?

What was the answer for mass at -50degrees.

That's the problem in some cases, confusion between the equation eV and the unit eV
As a unit, eV is electron volt so it must be multiplied by charge to make it J
As an equation eV is the total energy, like eV = 1/2mv^2

Oh well, lets not worry too much about it now

I'm pretty sure regardless we have both got 2 marks at least

I hope grade boundaries are low - by the sounds of it here, people found it quite easy.... my class found it tough though

fusion releases more energy than fission?

I agree that that's around the answer for the question, but you're still missing the point fission reactions produce more energy than fusion reactions. I understand that there is a greater change in binding energy, and hence more energy released PER NUCLEON, but since there are so many more nucleons in fission, it outputs more energy. Even though the change in binding energy is only around 1Mev per nucleon, there are around 200 nucleons involved, so it's much more

http://en.wikipedia.org/wiki/Nuclear_fission#Output

says that it's 200MeV

this isn't even the question so it doesn't really matter