Refraction: Solving Tricky Questions

[NewScientist]

1) Find the maximum refracting angle which a crown glass prism (1.52 refractive index) may have if sodium light is to pass through it with two refractions and no reflection? What deviation will be caused?

2) A beam of light strikes a water surface (refractive index 1.33) abd some of it is reflected by the surface and some is refracted. Find the angle of incidence of the beam of light if it is found that the refracted and the reflected rays are at right angle to each other.

I have no idea what to do!

I tried limiting Theta 1 and 2 in Snell's law but no luck!

Any help would be greatly recieved.

 

[finchie_88]

Not sure bout question 1, but for question 2, if you draw out a diagram, and try relating the angles to each other, I ended up with a situation where theta1 + theta2 equals 90 deg, and so using simultanius (I know its not spelt right) equations, the values of theta can be worked out (the other equations being relating the sin of the angles and the refractive index). That's what I think, but that doesn't mean its right. Best of luck with part 1.

 

[NewScientist]

^bump^^

please help!

 

[verty]

Did you solve question 2 yet? For question 1 I imagine you'd need to use the Sellmeier Equation (I found this out after some research, it's new to me). Apparently, 'sodium light' is yellow and has a wavelength of 589nm.