00:01
All right, so we have a beam of electrons undergoing a double -slit experiment, and they're incident on this slit screen, and then they're detected a meter away, and we're told the slit spacing distance is 10 micrometers, and that the third maximo, this is called us y3, is three centimeters from the central maxima, so we should have something like this.
00:29
And from this information alone i don't think there's any anything else we're given we want to know what is the potential delta v that these electrons are accelerated through as they are incident upon the slits okay so the idea is that the electrons have a certain energy entering in this and the energy is you have p squared over 2m so kinetic energy presumably and so this is going to be equal to the charge of the electron times the voltage difference through them.
01:03
We're just looking at magnitudes anyway.
01:08
So the momentum is the debroy momentum.
01:12
So h over lambda.
01:15
And so we got to find lambda ultimately.
01:17
And we can find lambda from the equation that for, you know, double slit experiment, you have d sine theta n equals n lambda.
01:25
And for this occasion, we're dealing with relatively small angles.
01:30
So the sign of theta is basically equal to theta.
01:33
And hence the tangent of theta is also basically equal to theta.
01:38
So like the tangent of theta is equal to the position of theta in is the position of the endth bright fringe divided by the screen distance.
01:51
And this is roughly equal to our angle.
01:53
So our angle is basically, if we plug these numbers in, it's about 0 .03 radiance.
01:58
And so that means that we have the wavelength from the first equation here is just going to be d times lambda over n...