2. What is Refraction of Light?
• Refraction is the bending of light when it
passes from one medium to another due to a
change in its speed.
3. Cause of Refraction
• Refraction occurs because light travels at
different speeds in different media.
4. Laws of Refraction
• 1. The incident ray, the refracted ray, and the
normal all lie in the same plane.
• 2. The ratio of the sine of the angle of
incidence to the sine of the angle of refraction
is constant (Snell's Law).
5. Snell's Law
• n1 * sin(i) = n2 * sin(r)
• Where:
• - n1 and n2 are refractive indices of medium 1
and 2
• - i is the angle of incidence
• - r is the angle of refraction
6. Refractive Index
• Refractive Index = Speed of light in vacuum /
Speed of light in the medium
• It is a measure of how much the light slows
down in a medium.
7. Refraction through Glass Slab
• When light passes through a rectangular glass
slab, the emergent ray is parallel to the
incident ray but displaced sideways.
8. Refraction by Lenses
• Convex lenses converge light rays, while
concave lenses diverge them. These effects
are due to refraction.
9. Applications of Refraction
• 1. Lenses in spectacles
• 2. Cameras
• 3. Microscopes and telescopes
• 4. Optical fibers
10. Atmospheric Refraction
• Refraction of light through the Earth's
atmosphere causes phenomena like the
twinkling of stars and apparent shift of the sun
during sunrise and sunset.
11. Experiment: Refraction through a
Glass Slab
• Apparatus: Glass slab, pins, paper, scale
• Procedure:
• 1. Place glass slab on paper.
• 2. Fix pins on one side and view from other
side.
• 3. Observe the bending of light and emergent
ray.
12. Conclusion
• Refraction is an important optical
phenomenon that explains many natural and
practical effects. It is governed by predictable
laws and formulas.
