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प्रश्न
List any five properties of light.
उत्तर
- Light is a form of energy.
- Light always travels along a straight line.
- Light does not need any medium for its propagation. It can even travel through a vacuum.
- The speed of light in a vacuum or air is c = 3 × 108 ms-1.
- Since light is in the form of waves, it is characterized by a wavelength (k) and a frequency (v), which are related by the following equation: c = v λ (c – velocity of light).
- Different coloured light has different wavelength and frequency.
- Among the visible light, violet light has the lowest wavelength and red light has the highest wavelength.
- When light is incident on the interface between two media, it is partly reflected and partly refracted.
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संबंधित प्रश्न
Differentiate between the luminous and non-luminous bodies. Give two examples of each.
Explain the difference between a transparent, a translucent, and an opaque medium. Give two examples of each.
Write the names of some cold light-emitting objects.
Answer the following.
What is light?
A ______ is a natural source of light.
When light passes through a prism, it gets separated into ______ colours.
Write whether of the following objects are luminous or non-luminous.
| Object | Luminous/Non-luminous |
| A book | |
| A burning candle | |
| A wax cloth | |
| A pencil | |
| A pen | |
| A light bulb | |
| A tyre | |
| A torch |
Light is a form of ______.
a) Draw ray diagrams to show how the image is formed using a concave mirror, when the position of object is:
- at C
- between C and F
- between F and P of the mirror.
b) Mention the position and nature of image in each case.
Observe the picture given in Fig. 11.1 carefully.
A patch of light is obtained at B, when the torch is lighted as shown. Which of the following is kept at position A to get this patch of light?
