Light is a form of electromagnetic radiation with a wavelength that can be detected by the human eye and it is also a form of energy.
This type of energy is called radiation. All sources of light produce radiant energy. We cannot see the radiant energy but when it falls on objects it makes the object visible. Light requires no material medium (like solid, liquid or gas). It can easily propagate in a vacuum. Sources of light are the things that can emit light are called the sources of light. Example: Natural source of light is Sun, stars, firefly, etc.Luminous source of light: the sources which emit their own light are known as luminous sources.Non-luminous sources of light: The bodies which do not have their own light but are visible after the light is incident on them from some Luminous sources are called non-luminous bodies. Let's know more about Light And Its Sources.
1. Which of the following is a luminous body?
A. Stars
B. Stone
C. Wood
D. Moon
2. Which of the following is non- luminous body?
A. Stars
B. Moon
C. Flame of candle
D. Sun
3. The energy whose wavelength is insensitive to the eye, called.
A. Mirror
B. Non-luminous
C. Luminous
D. Self-luminous
4.
The object which cannot emit light is called.
A. Non-luminous
B. Non lumin
C. Non luminena
D. Zee potency
5. Which of the following is the wavelength of red color?
A. 620-780 nm
B. 420-580 nm
C. 320-480 nm
D. 520-680 nm
6. What is the speed of light in the water medium?
A. 2.25*10^8
B. 1.25*10^8
C. 3.35*10^7
D. None of these
7. Which of the following is the wavelength of violet color?
A. 380-450 nm
B. 450-500 nm
C. 500-570 nm
D. 690-620 nm
8. The speed of light waves depends on the nature of the------------------.
A. Surrounding
B. Medium
C. Size
D. None of these
9. All sources of light produce-------------.
A. Radiant energy
B. Electric energy
C. Solar energy
D. None of these
10. Which of the following colors have a maximum refractive index?
A. Red colour
B. Violet colour
C. Green colour
D. Blue colour
11. The light reflected from the moon takes _________to reach the earth.
A. 1.50 second
B. 1.28 second
C. 1.07 second
D. 1.82 second
12. Two beams of light, one red and the other green fall on the same spot on a white screen. The color of the screen will appear to be--------------.
A. Magenta
B. Blue
C. Cyan
D. Yellow
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