# Refraction question help-physics

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#1
Hi I was wondering if someone would be able to help me with this question please.
Last edited by wonder girl; 5 months ago
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5 months ago
#2
(Original post by wonder girl)
Hi I was wondering if someone would be able to help me with this question please.
You want to use the equation: n1sinθ1 = n2sinθ2

θ1 = 30° as it is the angle of incidence (the angle between the normal to the prism's surface and the ray of light).
n1 = 1 as it's the refractive index of air.
n2 (for green light) = 1.515
n2 (for blue light) = 1.517

Hence:
n1sinθ1 = n2sinθ2
1 x sin(30) = 1.515sinθ2, where sinθ2 is the angle of refraction
1/2 = 1.515sinθ2
1.515/2 = sinθ2
Therefore, θ2 = arcsin(1.515/2) for the green light as it's path is changed in the prism

This can be done for the blue light to show that θ2 = arcsin(1.517/2)

Then you can store these values to memory and use them to calculate the difference between them.

For part b) refractive index tells us how fast light travels through the material. So for a higher refractive index, the speed of the light is slowed down more.

Consider the equation n1sinθ1 = n2sinθ2:
-If we investigate how the refractive index of a material (n2) affects the speed of light as it passes through the material
-n1sinθ1 is fixed, so if n2 is greater (e.g. passing light from air to diamond), sinθ2 must be smaller, hence θ2 must be smaller
-This means that for a higher refractive index, light is refracted MORE
-This means that the light has been slowed MORE

So since the green light has the smaller refractive index, it will travel faster through the material.

You could also mention that the amount of refraction increases for shorter wavelengths of light. So, blue light is refracted more/slowed more than green light.
2
#3
(Original post by WolfgangPauli)
You want to use the equation: n1sinθ1 = n2sinθ2

θ1 = 30° as it is the angle of incidence (the angle between the normal to the prism's surface and the ray of light).
n1 = 1 as it's the refractive index of air.
n2 (for green light) = 1.515
n2 (for blue light) = 1.517

Hence:
n1sinθ1 = n2sinθ2
1 x sin(30) = 1.515sinθ2, where sinθ2 is the angle of refraction
1/2 = 1.515sinθ2
1.515/2 = sinθ2
Therefore, θ2 = arcsin(1.515/2) for the green light as it's path is changed in the prism

This can be done for the blue light to show that θ2 = arcsin(1.517/2)

Then you can store these values to memory and use them to calculate the difference between them.

For part b) refractive index tells us how fast light travels through the material. So for a higher refractive index, the speed of the light is slowed down more.

Consider the equation n1sinθ1 = n2sinθ2:
-If we investigate how the refractive index of a material (n2) affects the speed of light as it passes through the material
-n1sinθ1 is fixed, so if n2 is greater (e.g. passing light from air to diamond), sinθ2 must be smaller, hence θ2 must be smaller
-This means that for a higher refractive index, light is refracted MORE
-This means that the light has been slowed MORE

So since the green light has the smaller refractive index, it will travel faster through the material.

You could also mention that the amount of refraction increases for shorter wavelengths of light. So, blue light is refracted more/slowed more than green light.
This has helped so much, thank you! Its such a detailed response!
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