00:01
Now we're given that the kinetic energy of the neutrons is 0 .04 ev.
00:12
We want to find what is the fraction of the neutrons that will decay before traveling a total distance of 10 kilometers.
00:26
Now we're given the half life, the half is 614 seconds.
00:32
So what we're going to do is going to use the kinetic energy to find what is the velocity, right? because it's half mv square.
00:39
After finding the velocity, we can find what is the time taken t to travel a distance of 10 kilometers.
00:50
And then from there we can use the decay law, which is n equals to n -e to power negative lambda t, to find what is the fraction, right? so take n over n0, which will equal to e negative lambda t.
01:07
So this is the fraction that we want that is left over, but what is the fraction that will decay.
01:16
So what we need is 1 minus of this particular fraction.
01:25
All right.
01:26
So now let us start.
01:30
We are given kinetic energy in terms of ev, so we'll have to first convert that into joust by dividing by 1 .6 times 10 power minus 19, juice per ev.
01:49
Sorry, it should not be multiplied, but it should be multiplied...