Advertisements
Advertisements
प्रश्न
The phenomena involved in the reflection of radiowaves by ionosphere is similar to ______.
पर्याय
reflection of light by a plane mirror.
total internal reflection of light in air during a mirage.
dispersion of light by water molecules during the formation of a rainbow.
scattering of light by the particles of air.
Advertisements
उत्तर
The phenomena involved in the reflection of radiowaves by ionosphere is similar to total internal reflection of light in air during a mirage.
Explanation:
Radio waves are reflected by a layer of the atmosphere called the Ionosphere, so they can reach distant parts of the Earth. The reflection of radio waves by ionosphere is due to total internal reflection. It is the same as total internal reflection of light in the air during a mirage, i.e., angle of incidence is greater than critical angle.
Important point: The ionized part of the Earth’s atmosphere is known as the ionosphere. Ultraviolet light from the sun collides with atoms in this region knocking electrons loose. The creates ions or atoms with missing electrons. This is what gives the Ionosphere its name- and it is the free electrons that cause the reflection and absorption of ratio waves.
APPEARS IN
संबंधित प्रश्न
A ray of light travels from water to air as shown in the diagram given below :
1) Copy the diagram and complete the path of the way. Given the critical angle for water is 48°.
2) State the condition so that internal reflection occurs in the above diagram.
What is total internal reflection?
Total internal reflection can take place only if ______.
(a) A ray of monochromatic light enters glass PQRS as shown in the fig. Complete the path of ray till it emerges from the glass. (Critical angle of glass is 420).
(b) Draw diagram of a prism periscope.
(c) What are the advantages of total internal reflecting prism over plane mirror?
How does a ray of light bend when it travels from when it is normal to the interface of the two media.
Write down the relationship between the critical angle and the refractive index of the medium.
Express the refractive index μ of a medium in terms of the angle of incidence i in air and the angle of refraction r in a denser medium.
State two advantages of using a right-angle prism as a reflector, rather than a plane mirror.
A ray of light incident at an angle of incidence ‘i’ passes through an equilateral glass prism such that the refracted ray inside the prism is parallel to its base and emerges from the prism at an angle of emergence ‘e’.
How is the angle of emergence ‘e’ related to the angle of incidence ‘i’?
What is meant by the statement, ‘the critical angle for diamond is 24°’?
How is the critical angle of a material related to its refractive index?
Explain ‘mirage’ as an illustration of refraction.
Solve Numerical example.
A monochromatic ray of light is incident at 37° on an equilateral prism of refractive index 3/2. Determine angle of emergence and angle of deviation. If angle of prism is adjustable, what should its value be for emergent rays to be just possible for the same angle of incidence?
For the same angle of incidence, the angle of refraction in four media A, B, C and D are 25°, 30°, 35° and 40° respectively. The speed of light is least in medium ______.
For a ray of light, the critical angle is minimum when it travels from ______.
Total internal reflection can take place only if light is travelling from ______.
Which of the following statements about total internal reflection is true?
State the condition under which total internal reflection occurs. Give the mathematical expression for total internal reflection.
The diagram below shows a fish in the tank and its image seen on the surface of the water.
Name the phenomenon responsible for the formation of this image.
