The statement “The refractive index of diamond is 2.42” means that the speed of light in diamond is 2.42 times slower than its speed in a vacuum. The refractive index quantifies how much a material bends or refracts light. A refractive index of 2.42 indicates that diamond significantly alters the path of light passing through it, causing a notable bending effect. This high refractive index contributes to diamond’s characteristic brilliance and sparkle.


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Introduction to Refractive Index

Fundamental Optical Property: The refractive index of a material is a key optical property that indicates how much the material bends, or refracts, light. It is a dimensionless number that compares the speed of light in the material to its speed in a vacuum.

Refractive Index of Diamond

High Value Indicating Strong Refraction: A refractive index of 2.42 for diamond is significantly higher than that of many other materials. This high value implies that light traveling through diamond is refracted, or bent, to a great extent.

Speed of Light in Diamond

Slower Than in Vacuum: The refractive index of 2.42 means that light travels through diamond at a speed that is 2.42 times slower than its speed in a vacuum. This slowing down is a result of the light interacting with the atomic structure of the diamond.

Light Bending in Diamond

Cause of Brilliance and Sparkle: The high refractive index of diamond causes light to bend sharply when it enters the gemstone. This bending, or refraction, is responsible for the characteristic brilliance and sparkle of diamonds, as it leads to significant dispersion of light into its constituent colours.

Comparison with Other Materials

Relative Optical Density: The refractive index of 2.42 places diamond among materials with very high optical densities. This is in contrast to materials like air or water, which have lower refractive indices and thus bend light to a lesser degree.

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Implications of High Refractive Index: The statement that diamond has a refractive index of 2.42 highlights its exceptional ability to refract light. This property is not only key to its aesthetic appeal in jewelry but also important in various industrial and technological applications where precise light manipulation is required.

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Questions of 10th Science Chapter 9 in Detail

Define the principal focus of a concave mirror.
The radius of curvature of a spherical mirror is 20 cm. What is its focal length?
Name a mirror that can give an erect and enlarged image of an object.
Why do we prefer a convex mirror as a rear-view mirror in vehicles?
Find the focal length of a convex mirror whose radius of curvature is 32 cm.
A concave mirror produces three times magnified (enlarged) real image of an object placed at 10 cm in front of it. Where is the image located?
A ray of light travelling in air enters obliquely into water. Does the light ray bend towards the normal or away from the normal? Why?
Light enters from air to glass having refractive index 1.50. What is the speed of light in the glass?
Find out, from Table, the medium having highest optical density. Also find the medium with lowest optical density.
You are given kerosene, turpentine and water. In which of these does the light travel fastest?
The refractive index of diamond is 2.42. What is the meaning of this statement?
Define 1 dioptre of power of a lens.
A convex lens forms a real and inverted image of a needle at a distance of 50 cm from it. Where is the needle placed in front of the convex lens if the image is equal to the size of the object?
Find the power of a concave lens of focal length 2 m.
We wish to obtain an erect image of an object, using a concave mirror of focal length 15 cm. What should be the range of distance of the object from the mirror?
Name the type of mirror used in the following situations. (a) Headlights of a car. (b) Side/rear-view mirror of a vehicle. (c) Solar furnace.
One-half of a convex lens is covered with a black paper. Will this lens produce a complete image of the object?
An object 5 cm in length is held 25 cm away from a converging lens of focal length 10 cm. What is the position, size and the nature of the image formed.
A concave lens of focal length 15 cm forms an image 10 cm from the lens. How far is the object placed from the lens?
An object is placed at a distance of 10 cm from a convex mirror of focal length 15 cm. Find the position and nature of the image.
The magnification produced by a plane mirror is +1. What does this mean?
An object 5.0 cm in length is placed at a distance of 20 cm in front of a convex mirror of radius of curvature 30 cm. Find the position of the image, its nature and size.
An object of size 7.0 cm is placed at 27 cm in front of a concave mirror of focal length 18 cm. At what distance from the mirror should a screen be placed, so that a sharp focussed image can be obtained?
Find the focal length of a lens of power – 2.0 D. What type of lens is this?
A doctor has prescribed a corrective lens of power +1.5 D. Find the focal length of the lens. Is the prescribed lens diverging or converging?