Fresnel Biprism
Hi,
So I'm really stuck on this experiment I've been doing with the Fresnel Biprism (I'm supposed to find the wavelength of the laser shining through it). I know how to find this (essentially the same as Young's Double slit), but I can't figure out how I'm supposed to find the virtual slit opening.
I've done the other part of the experiment where I varied the distance between the screen and the laser, and measured the width of the interference, but I can't see how to find the slit opening. All I know is that the angle of the Biprism itself is 1 degree.
I've read in a few places that you're supposed to use a convex lens and somehow make two measurements of a separation... but firstly we are given concave lenses, and secondly I am just very confused.
Any help, please? Thanks!
