laws of refraction of light class 10 with diagram:
- The incident ray, refracted ray, and the normal to the interface of two media lie in the same plane at the point of incidence.
- The ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant. This is also known as Snell’s law of refraction.
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The diagram of refraction of light in glass slab:
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Laws of refraction:
- At the point of incidence, the incident ray, refracted ray, and normal to the interface of two media all lie on the same plane.
- The sine of the angle of incidence to sine of the angle of refraction ratio is constant. Snell’s law of refraction is another name for this.
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- When a ray of light passes from an optically rarer medium to a denser medium it bends towards the normal(∠r < ∠i), as shown in figure (a).
- When a ray of light passes from an optically denser to a rarer medium it bends away from the normal (∠r> ∠i) as shown in figure (b).
- A ray of light traveling along the normal passes undeflected, as shown is figure (c). Here ∠i = ∠r = 0.
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Cause of Refraction of refraction of light
- Refraction is the deviation of light when it crosses the boundary between two different media (of different optical densities) and there is a change in both the wavelength and the speed of light.
- The frequency of the refracted ray remains unchanged.
- The intensity of the refracted ray is less than that of the incident ray. It is because there is partial reflection and absorption of light at the interface.
Effects of refraction of Light:
- If a straight stick is partially put in water, it appears to be bent.
- If we see a water tank its bottom appears to e raises. It also appears to be concave shaped although it is flat.
- The sun is visible a few minutes earlier than it actually rises above horizon, because as we go up from earth, the density of air layer decrease, then rays from sun keep on bending towards normal till it enters the eye.
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REFRACTIVE INDEX:
(a) Refractive Index in terms of Speed of Light:
The refractive index of a medium may be defined in terms of the speed of light as follows :
The refractive index of a medium for a light of given wavelength may be defined at the ratio of the speed of light in vacuum to its speed in that medium.
b) Relative Refractive Index:
The relative refractive index of medium 2 with respect to medium 1 is defined as the ratio of speed of light (v1) in the medium 1 to the speed of light (v2) in medium 2 and is denoted by .
Thus
Refractive index=Speed of light in Vacuum/speed of light in medium.
laws of refraction of light class 10 with diagram(और अधिक समझने के लिए विडियो देखें और दोस्तों को भी शेयर करे|)
laws of refraction of light class 10 ( Some important questions)
Q.1) Light enters from air into a glass plate having refractive index 1.50. what is the speed of light in glass.
Solution:-µ =1.50 Speed of light =3×108 m/s
µ= Speed of light in Vacuum/Speed of light in medium
∴ µ= 3×108/ Speed of light in glass
So, Speed of light in glass=1.50/ 3×108
∴ Speed of light in glass=2×108 m/s
Refractive index for light going from one medium to 2 medium is equal to the reciprocal of the refractive index for light going from medium 2 to medium 1.
(1)For the light going from medium 1 to medium 2 the refractive index is given by
1μ2=v1/v2
(2)And for the light going grom medium 2 to medium 1 the refractive index is given by
2μ1=v2/v1
Let us take the reciprocal of this equation
1/2μ1=v1/v2
From equation 1 and 2 we have
1μ2 =1/2μ1
Medium 1 µ medium 2=1/Medium 2µ medium1
This means that the refractive index for light going from medium 1 to medium 2 is equal to the reciprocal of refractive index for light going from medium 2 to medium 1.
More Resources for CBSE Class 10
- NCERT Solutions
- NCERT Solutions for Class 10 Science
- NCERT Solutions for Class 10 Maths
- NCERT Solutions for Class 10 Social
- NCERT Solutions for Class 10 English
- NCERT Solutions for Class 10 Hindi
- NCERT Solutions for Class 10 Sanskrit
- NCERT Solutions for Class 10 Foundation of IT
- RD Sharma Class 10 Solutions
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