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प्रश्न
What is the speed of light in vacuum?
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उत्तर
The speed of light in vacuum is known to be almost exactly 300,000 km per second. In 1665 the Danish astronomer Ole Roemer first estimated the speed of light by observing one of the twelve moons of the planet Jupiter.
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संबंधित प्रश्न
State the speed of light in (a) air, (b) glass.
State whether light slows down or speeds up in the following cases :
Light going from air to glass.
State whether light slows down or speeds up in the following cases :
Light going from water to air.
A light ray passes from water to
- air, and
- glass.
In each case, state how does the speed of light change.
The speed of light is maximum in ______.
Numerical problem.
Light enters from air into a glass plate having refractive index 1.5. What is the speed of light in glass? (Ans: 2 × 108 ms–1)
Higher Order Thinking Skills.
Light ray emerges from water into air. Draw a ray diagram indicating the change in its path in water.
Objects that allow light to pass through partially are called ______ material.
Define opaque material.
Higher-Order Thinking Skills:
M = 2.42 for diamond. What is the meaning of this statement in relation to the speed of light?
