Is My Calculation of Light Refraction and Wavelength in Water Correct?

AI Thread Summary
The calculation of light refraction and wavelength in water is confirmed to be correct, with an angle of refraction of approximately 25.5 degrees and a wavelength of 441.86 nm in water. The second problem involves finding the angle of incidence when reflected and refracted rays are perpendicular, which leads to the equation sin(Theta1) = n*cos(Theta1). Suggestions include using the relationship between angles and the sine and cosine functions to solve for Theta1. However, the user expresses difficulty in arriving at a definitive solution for this part. The discussion emphasizes the importance of correctly applying trigonometric identities in optics problems.
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Could someone tell me if I did this right?
A narrow beam of sodium yellow light, with wavelength 589 nm in vacuum, is incident from air onto a smooth water surface at an angle of incidence of 35.0 degrees. Determine the angle of refraction and the wavelength of the light in water.
I did...
sin(35 degrees)=1.333*sin(theta)
theta = 25.486 degrees

589 nm = 1.333*lambda
lambda = 441.86

I'm just not sure I used the right equation/setup.

And I can't figure out this problem...
Unpolarized light in vacuum is incident onto a sheet of glass with index of refraction n. The reflected and refracted rays are perpendicular to each other. Find the angle of incidence.
I figured Theta1 + Theta2 = 90 degrees
and I tried to find a way to solve it using sin(Theta1) = n*sin(Theta2) but it's not working out.

Thanks.
 
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The first part looks right to me I guess. Think about \Theta_2 = 90 - \Theta_1 and plug it into your formula. Remember that sin(90-x) = cos(x)
 
vsage said:
The first part looks right to me I guess. Think about \Theta_2 = 90 - \Theta_1 and plug it into your formula. Remember that sin(90-x) = cos(x)

I've tried it that way, I wasn't able to get anywhere with it.
 
I don't really see a definitive answer for part 2, but since sin(\theta_1) = n\times cos(\theta_1), \theta_1 = tan^{-1}(n)
 
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