notes of chapter refraction and reflection class 10
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Answer:
In Pushing a wall no work is being done. ... Internal work is being done by muscle cell, sowe loose energy, where as in particle physics,work done by a force can only be said when that force displaces the body (in the direction of force applied )on which it is applied.Constitution of 1791, French constitution created by the National Assembly during the French Revolution. It retained the monarchy, but sovereignty effectively resided in the Legislative Assembly, which was elected by a system of indirect voting.Constitution of 1791, French constitution created by the National Assembly during the French Revolution. It retained the monarchy, but sovereignty effectively resided in the Legislative Assembly, which was elected by a system of indirect voting.In Pushing a wall no work is being done. ... Internal work is being done by muscle cell, sowe loose energy, where as in particle physics,work done by a force can only be said when that force displaces the body (in the direction of force applied )on which it is applied.
Answer:
Explanation:
Refraction is the bending of a wave when it enters a medium where its speed is different. The refraction of light when it passes from a fast medium to a slow medium bends the light ray toward the normal to the boundary between the two media. The amount of bending depends on the indices of refraction of the two media and is described quantitatively by Snell's Law.
Refraction is responsible for image formation by lenses and the eye.
The bending of refraction can be visualized in terms of Huygen's principle. As the speed of light is reduced in the slower medium, the wavelength is shortened proportionately. The frequency is unchanged; it is a characteristic of the source of the light and unaffected by medium changes.
Refraction and the eye Refraction of sound
Refraction of light by water Refraction and focal length
Index
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Index of Refraction
The index of refraction is defined as the speed of light in vacuum divided by the speed of light in the medium.
The indices of refraction of some common substances are given below with a more complete description of the indices for optical glasses given elsewhere. The values given are approximate and do not account for the small variation of index with light wavelength which is called dispersion.
Material
n
Material
n
Vacuum
1.000
Ethyl alcohol
1.362
Air
1.000277
Glycerine
1.473
Water
4/3
Ice
1.31
Carbon disulfide
1.63
Polystyrene
1.59
Methylene iodide
1.74
Crown glass
1.50-1.62
Diamond
2.417
Flint glass
1.57-1.75
Refraction and the eye Refraction of sound
Table of refractive indices
Index
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Snell's Law
Snell's Law relates the indices of refraction n of the two media to the directions of propagation in terms of the angles to the normal. Snell's law can be derived from Fermat's Principle or from the Fresnel Equations.
Enter data below, then click the symbol of the quantity you wish to calculate.
Indices of refraction:
=
=
Angles with surface normal:
=
°
=
°
Enter data and then click on the symbol for the quantity you wish to calculate in the active equation above. The numbers will not be forced to be consistent until you click on the quantity to calculate. Indices of refraction must be greater than or equal to 1, so values less than 1 do not represent a physically possible system.
If the incident medium has the larger index of refraction, then the angle with the normal is increased by refraction. The larger index medium is commonly called the "internal" medium, since air with n=1 is usually the surrounding or "external" medium. You can calculate the condition for total internal reflection by setting the refracted angle = 90° and calculating the incident angle. Since you can't refract the light by more than 90°, all of it will reflect for angles of incidence greater than the angle which gives refraction at 90°.