Consider the optical interface between crown glass and ethanol. Under what conditions would total internal relfection be possible at this interface? ilustrate your answer with a light ray diagram.
Okay so you need the angle of incidenc to be greater than the critical angle AND the light must be travelling from a medium of higher index refraction into a medium of lower index of refraction.
Im just confused with the diagram part.
I have my axis drawn, with crown glass on top since its higher index of refraction, and then water below. But now I don't know how to draw the arrow.
draw the normal. then, the light in starting from inside the glass, traveling at the angle of incidence, hits the alcohol/glass interface, then is refraced from the normal 90 degrees (tangent to the interface). The incident angle in the glass (measured to the normal) is the critical angle.
so, both arrows should remain on the crown glass side of the axis, correct? t should just sort of look like a "V"?
To draw the light ray diagram, follow these steps:
1. Draw a horizontal line to represent the surface separating the crown glass and ethanol. Place the crown glass on top and the ethanol below.
2. Draw a vertical line at the boundary between the two mediums to represent the normal line.
3. To depict the incident ray, draw an incoming line at an angle of incidence (θi) with respect to the normal line. The angle of incidence should be greater than the critical angle for total internal reflection to occur. The incident ray should originate from a point above the interface, typically represented by an arrowhead.
4. Since the light is traveling from a medium of higher refractive index (crown glass) to a medium of lower refractive index (ethanol), the incident ray should bend away from the normal line. This bending is known as refraction.
5. Draw a dotted line to represent the refracted ray. The angle of refraction (θr) can be determined using Snell's law, which states that the ratio of the sine of the angle of incidence to the sine of the angle of refraction is equal to the ratio of the refractive indices of the two mediums. In this case, n1sin(θi) = n2sin(θr), where n1 represents the refractive index of crown glass and n2 represents the refractive index of ethanol.
6. If the angle of incidence is greater than the critical angle (θc), total internal reflection occurs. The critical angle can be calculated using the equation sin(θc) = n2/n1. If the angle of incidence is larger than the critical angle, the refracted ray will not emerge into the ethanol and will instead reflect back into the crown glass.
So, in summary, draw the incident ray originating from above the interface, bending away from the normal line, and if the angle of incidence is larger than the critical angle, the refracted ray should be drawn reflecting back into the crown glass.