Advertisements
Advertisements
Question
Explain: ‘How is a rainbow formed’?
Advertisements
Solution
1. The beautiful phenomenon of the rainbow is a combination of different phenomena – dispersion, refraction, and reflection of light.
2. The rainbow appears in the sky after a rain shower.
3. The water droplets act as small prisms.
4. When sunlight enters the water droplets present in the atmosphere, they refract and disperse the incident sunlight.
5. Then they reflect it internally inside the droplet and finally again refract it.
6. As a collective effect of all these phenomena, the seven-colored rainbows are observed.
APPEARS IN
RELATED QUESTIONS
Why can’t we see clearly through fog?
Why does unpolarised light from a source show a variation in intensity when viewed through a polaroid which is rotated?
Draw the intensity distribution for the fringes produced in interference ?
Draw the intensity distribution for the diffraction bands produced due to single slit ?
Write two points of difference between the phenomena of interference and diffraction.
What is linearly polarized light?
The image formed by a concave mirror
A parallel beam of light is incident on a converging lens parallel to its principal axis. As one moves away from the lens on the other side on its principal axis, the intensity of light
A thin lens is made with a material having refractive index
\[\mu = 1 \cdot 5\]. Both the side are convex. It is dipped in water \[\mu = 1 \cdot 33\]. It will behave like
A concave mirror having a radius of curvature 40 cm is placed in front of an illuminated point source at a distance of 30 cm from it. Find the location of the image.
A converging mirror M1, a point source S and a diverging mirror M2 are arranged as shown in figure. The source is placed at a distance of 30 cm from M1. The focal length of each of the mirrors is 20 cm. Consider only the images formed by a maximum of two reflections. It is found that one image is formed on the source itself. (a) Find the distance between the two mirrors. (b) Find the location of the image formed by the single reflection from M2.
A cylindrical vessel, whose diameter and height both are equal to 30 cm, is placed on a horizontal surface and a small particle P is placed in it at a distance of 5.0 cm from the centre. An eye is placed at a position such that the edge of the bottom is just visible (see figure). The particle P is in the plane of drawing. Up to what minimum height should water be poured in the vessel to make the particle P visible?
An optical fibre (μ = 1.72) is surrounded by a glass coating (μ = 1.50). Find the critical angle for total internal reflection at the fibre-glass interface.
Answer the following question in detail.
State the conditions under which a rainbow can be seen.
Answer the following question in detail.
Explain the formation of a primary rainbow. For which angular range with the horizontal is it visible?
Answer the following question in detail.
Explain the formation of a secondary rainbow. For which angular range with the horizontal is it visible?
State any one difference between a primary rainbow and a secondary rainbow.
| Case study: Mirage in deserts |
 |
|
To a distant observer, the light appears to be coming from somewhere below the ground. The observer naturally assumes that light is being reflected from the ground, say, by a pool of water near the tall object. Such inverted images of distant tall objects cause an optical illusion to the observer. This phenomenon is called mirage. This type of mirage is especially common in hot deserts. Based on the above facts, answer the following question : |
A diver at a depth 12 m inside water `(a_(µω) = 4/3)` sees the sky in a cone of semi-vertical angle
A passenger in an aeroplane shall ______.
