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प्रश्न
Answer the following question in detail.
State the conditions under which a rainbow can be seen.
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उत्तर
A rainbow can be observed when there is a light shower with a relatively large raindrop occurring during morning or evening time with enough sunlight around.
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संबंधित प्रश्न
Show with the help of a diagram, how unpolarised light from Sun gets linearly polarised by scattering.
Draw the intensity distribution for the fringes produced in interference ?
Write two points of difference between the phenomena of interference and diffraction.
In the meterbridge experimental set up, shown in the figure, the null point ‘D’ is obtained at a distance of 40 cm from end A of the meterbridge wire. If a resistance of 10Ω is connected in series with R1, null point is obtained at AD = 60 cm. Calculate the values of R1 and R2.
Describe briefly using a diagram how sunlight is polarised ?
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 candle flame 1.6 cm high is imaged in a ball bearing of diameter 0.4 cm. If the ball bearing is 20 cm away from the flame, find the location and the height of the image.
A point source S is placed midway between two converging mirrors having equal focal length f as shown in figure. Find the values of d for which only one image is formed.
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?
Light is incident from glass (μ = 1.50) to water (μ = 1.33). Find the range of the angle of deviation for which there are two angles of incidence.
Light falls from glass (μ = 1.5) to air. Find the angle of incidence for which the angle of deviation is 90°.
A point source is placed at a depth h below the surface of water (refractive index = μ). (a) Show that light escapes through a circular area on the water surface with its centre directly above the point source. (b) Find the angle subtended by a radius of the area on the source.
A biconvex thick lens is constructed with glass (μ = 1.50). Each of the surfaces has a radius of 10 cm and the thickness at the middle is 5 cm. Locate the image of an object placed far away from the lens.
One end of a cylindrical glass rod (μ = 1.5) of radius 1.0 cm is rounded in the shape of a hemisphere. The rod is immersed in water (μ = 4/3) and an object is placed in the water along the axis of the rod at a distance of 8.0 cm from the rounded edge. Locate the image of the object.
A paperweight in the form of a hemisphere of radius 3.0 cm is used to hold down a printed page. An observer looks at the page vertically through the paperweight. At what height above the page will the printed letters near the centre appear to the observer?
The diameter of the sun is 1.4 × 109 m and its distance from the earth is 1.5 × 1011 m. Find the radius of the image of the sun formed by a lens of focal length 20 cm.
Explain: ‘How is a rainbow formed’?
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?
A parallel beam of light of wavelength 5890 Å falls normally on a slit of width 0.2 mm. Find the distance between the first minima on the two sides of the central maximum of the diffraction pattern observed on a screen placed in the focal plane of a convex lens of focal length 50 cm. The lens is placed quite close to the slit.
| Case study: Mirage in deserts |
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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: |
Which of the following phenomena is prominently involved in the formation of mirage in deserts?
| 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 diamond is immersed in such a liquid which has its refractive index with respect to air as greater than the refractive index of water with respect to air. Then the critical angle of diamond-liquid interface as compared to critical angle of diamond-water interface will
