by Tiwari Academy
The speed of light in a medium is inversely related to its refractive index: the lower the refractive index, the faster light travels through the medium. Among kerosene, turpentine, and water, water has the lowest refractive index (approximately 1.33). Kerosene and turpentine have higher refractive indices, around 1.4 and 1.47 respectively. Therefore, light travels fastest in water compared to kerosene and turpentine due to its lower refractive index.
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Introduction to Light Speed in Different Media
Fundamentals of Light Propagation: The speed at which light travels through a medium is determined by the medium’s refractive index. The lower the refractive index, the less the light is slowed down, and thus, the faster it travels through that medium.
Understanding Refractive Index
Indicator of Light Speed: The refractive index of a substance is a measure of how much it reduces the speed of light compared to its speed in a vacuum. A lower refractive index means light can travel through the medium more quickly.
Refractive Indices of Common Liquids
Comparing Kerosene, Turpentine, and Water: Among the given liquids – kerosene, turpentine, and water – each has a different refractive index. Water typically has a refractive index of about 1.33. Kerosene’s refractive index is around 1.4, and turpentine’s is approximately 1.47.
Light Speed in Water
Fastest in Water: Given these refractive indices, light travels fastest in water. Its lower refractive index compared to kerosene and turpentine means that light is less slowed down in water.
Light Speed in Kerosene and Turpentine
Comparatively Slower: In kerosene and turpentine, the higher refractive indices indicate that light travels slower in these liquids compared to water. The denser the medium (in terms of optical density), the more it slows down the light.
NCERT Solutions App
Optimal Medium for Light Speed: Therefore, among kerosene, turpentine, and water, light travels fastest in water due to its lowest refractive index. This principle is crucial in understanding the behaviour of light in different environments and has practical applications in optics and photonics.
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Questions of 10th Science Chapter 9 in Detail
