What is refraction?
The bending of light as it passes from one medium into another of different optical density.
State the law of refraction (Snell’s Law).
\[ n = \frac{\sin i}{\sin r} \]
Define refractive index.
The ratio of the speed of light in vacuum to the speed of light in the medium: \[ n = \frac{\text{speed of light in vacuum }}{\text{speed of light in medium }} \]
What is the formula relating real and apparent depth?
\( n = \frac{\text{Real depth}}{\text{Apparent depth}} \)
What causes refraction of light?
Refraction occurs because light travels at different speeds in different media.
What is total internal reflection?
The complete reflection of light within a medium when the angle of incidence exceeds the critical angle.
What is the formula for critical angle?
\( \sin C = \frac{1}{n} \)
What is dispersion of light?
The separation of white light into its component colors due to different refraction of each color.
Which color is least refracted in a prism?
Red.
Which color is most refracted in a prism?
Violet.
What is white light made up of?
Seven colors: red, orange, yellow, green, blue, indigo, and violet (ROYGBIV).
What is the angle of refraction when the angle of incidence is the critical Angle?
\[ \text{angle of refraction} = 90^\circ \]
State the effect of refraction on the appearance of objects in water.
Objects appear shallower than they actually are.
What is the speed of light in air?
Approximately \( 3 \times 10^8 \) m/s.
What happens to the wavelength of light when it enters a denser medium?
The wavelength decreases.
What happens to the frequency of light during refraction?
The frequency remains unchanged.
What are primary colors of light?
Red, green, and blue.
What are secondary colors of light?
Yellow (red + green), magenta (red + blue), and cyan (green + blue).
What is the result of mixing all primary colors of light?
White light.
What happens to a light ray when it enters a denser medium?
It bends towards the normal.
What happens to a light ray when it moves from a denser to a less dense medium?
It bends away from the normal.
What are the conditions for total internal reflection?
The light must travel from a denser to a less dense medium and the angle of incidence must be greater than the critical angle.
What is the critical angle for glass (n = 1.5)?
\( \sin C = \frac{1}{1.5} \Rightarrow C \approx 41.8^\circ \)
What is the refractive index formula using angles?
\( n = \frac{\sin i}{\sin r} \)
What is the relationship between the refractive index and the angle of deviation
\[ n = \frac{\sin \left( \frac{A}{2} + \frac{D}{2} \right)}{\sin \frac{A}{2}} \]
Describe the path of light through a triangular prism.
Light is refracted twice, once upon entering and once upon leaving the prism, causing deviation and dispersion.
What is the angle of deviation in a prism?
The angle between the incident ray and the emergent ray.
What is lateral inversion?
The reversal of left and right in an image, such as with a mirror.
What is the relationship between speed of light and refractive index?
\( n = \frac{c}{v} \), where \( c \) is the speed of light in vacuum and \( v \) in the medium.
Why do stars appear to twinkle?
Due to refraction of starlight by layers of the atmosphere with varying densities.
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