Solve Angle Between Light Rays After Prism Refraction - Help (with prism)

  • Thread starter Thread starter shingetsunohimitsu
  • Start date Start date
  • Tags Tags
    Prism
AI Thread Summary
The discussion centers on calculating the angle between two parallel light rays after they pass through a prism with a refractive index of 1.48 and an entry angle of 30 degrees. Participants express confusion about the geometry of the situation, particularly regarding the rays' entry points and whether they strike the same internal surfaces of the prism. There is a consensus that if the rays are parallel upon entering and interact with the same walls, they should remain parallel after exiting. Additionally, a warning is raised about the incorrect use of arcsin with values greater than 1, emphasizing the need for clarity in the calculations. Overall, clearer descriptions or diagrams of the prism and ray paths are requested to facilitate understanding.
shingetsunohimitsu
Messages
7
Reaction score
0
Help

34-31. The prism of the figure has a refractive index of 1.48, and the angles A are 30.0°. Two light rays m and n are parallel as they enter the prism. What is the angle between them after they emerge?
I. Set the hypotenuse of the small triangle to the left at 10cm. Gives you a triangle which is 5^2+8.66^2=10^2
II. The angle should be arccos(5/10)=60.0°
III. The angle of refraction should be arcsin(1.281)
The angle they make with the base of the prism should be arcsin(1.281)+30.0°, In which case the angle they make towards each other is as much 2(arcsin(1.281)+30.0°)


Now, the answer, I'm sure is completely off the hooks.

I'm new around, I don't have a university degree, only what's equivalent to basic high school maths and a burning passion for physics. My dabbling in the arts are meagre, and I want to ask pardon my stupid questions before anyone gets the chance to demand a pardon from me. There you go.
In all my humbleness
/Shingetsu
 
Physics news on Phys.org
I'm having a hard time picturing the situation. Do the two rays enter the hypotenuse of the triangle with an angle of incidence of 30 degrees? AFter they enter the prism, which internal side do they hit? Do both rays hit the same side internally?

If the two rays are parallel when coming in, and they have do not have different index of refraction, and they hit the same walls of the prism, they should emerge parallel to each other.

And you can't have an arcsin of a number greater than 1.00, so figure out what you meant by that.
 
If you can attach a figure, that will help us understand what's going on. As chi meson said, it's not clear why the emergent rays should not be parallel too - unless they don't go in the same side.

If you have absolutely no means of providing a figure, try describing the prism and the ray directions more clearly.
 
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
Back
Top