by Chris Peterson » Wed Sep 12, 2012 2:46 pm
Markus Schwarz wrote:Chris Peterson wrote:[...] return signal of 0.003 photons for a single 1e32 photon isotropic pulse.
The site doesn't like that answer, so either the site is wrong, or I'm misunderstanding the question
I made the same mistake at first. They require you to
round to the nearest whole number, which is 0 in this case. Still, I would prefer that they accept 0.003 as well.
Ha. Borderline trick question. Funny thing is that I tried a couple of alternatives based on possible errors- using one parsec, forgetting to square the radius, and got larger numbers... which I
did round to the nearest whole number.
The problem with rounding a very small fractional value to zero is that it actually gives a
completely wrong answer. If you genuinely took zero to be the answer here, the conclusion would be that there is no point in sending the probe at all. 0.003 tells us we need a more intense pulse, or more pulses. Rounding up to one would be better than rounding to zero.
[quote="Markus Schwarz"][quote="Chris Peterson"][...] return signal of 0.003 photons for a single 1e32 photon isotropic pulse.
The site doesn't like that answer, so either the site is wrong, or I'm misunderstanding the question[/quote]
I made the same mistake at first. They require you to [b]round to the nearest whole number[/b], which is 0 in this case. Still, I would prefer that they accept 0.003 as well.[/quote]
Ha. Borderline trick question. Funny thing is that I tried a couple of alternatives based on possible errors- using one parsec, forgetting to square the radius, and got larger numbers... which I [i]did [/i]round to the nearest whole number.
The problem with rounding a very small fractional value to zero is that it actually gives a [i]completely [/i]wrong answer. If you genuinely took zero to be the answer here, the conclusion would be that there is no point in sending the probe at all. 0.003 tells us we need a more intense pulse, or more pulses. Rounding up to one would be better than rounding to zero.