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Assertion: Average power in an AC circuit is given by `P=I_(rms)^2 R` . Reason: In one full cycle, net power is dissipated not only in a

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Suppose while sitting in a parked car, you notice a jogger approaching towards you in the side view mirror of R = 2 m. If the jogger is running at a speed of 5 m s–1, how fast the image of the jogger appear to move when the jogger is

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The earth takes 24 h to rotate once about its axis. How much time does the sun take to shift by 1º when viewed from the

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The radii of curvature of the faces of a double convex lens are 10 cm and 15 cm. Its focal length is 12 cm. What is the refractive index of

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Explain: A virtual image, we always say, cannot be caught on a screen. Yet when we ‘see’ a virtual image, we are obviously bringing it on to the ‘screen’ (i.e., the retina) of our eye. Is there a

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An angular magnification (magnifying power) of 30X is desired using an objective of focal length 1.25cm and an eyepiece of focal length 5cm. How will you set up the compound

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Why does bluish colour predominate in a clear

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A biconvex lens made of a transparent material of refractive index 1.5 is immersed in a water of refractive index 1.33. Will the lens behave as a converging or a diverging lens? Give

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A biconvex lens has a focal length 2/3 times the radius of curvature of either surface. Calculate the refractive index of lens

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(i) Out of blue and red light, which is deviated more by a prism? Give reason. (ii) Give the formula that can be used to determine refractive index of material of a prism in minimum deviation

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(i) State the principle on which the working of an optical fibre is based. (ii) What are the necessary conditions for this phenomenon to

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(i) What is the relation between critical angle and refractive index of a material? (ii) Does critical angle depend on the colour of light?

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You are given three lenses `L_1,L_2 and L_3` each of focal length 10 cm. An object is kept at 15 cm in front of `L_1` as shown. The final real image is formed at the focus `I` of `L_3` . Find the separation between `L_1, L_2 and

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(i) Draw a labelled ray diagram showing the formation of a final image by a compound microscope at least distance of distinct vision. (ii) The total magnification produced by a compound microscope is 20. The magnification produced by the eyepiece is 5. The microscope is focused on a certain object. The distance between the objective and eyepiece is observed to be 14 cm. If least distance of distinct vision is 20 cm. Calculate the focal length of the objective and the

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(i) Draw a labelled ray diagram showing the image formation of a distant object by refracting telescope. Deduce the expression for its magnifying power when the final image is formed at infinity. (ii) The sum of focal lengths of the two lenses of a refracting telescope is 105 cm. The focal length of one lens is 20 times that of the other. Determine the total magnification of the telescope when the final image is formed at

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A beam of light consisting of two wavelengths, 650 nm and 520 nm, is used to obtain interference fringes in a Young’s double-slit experiment. What is the least distance from the central maximum where the bright fringes due to both the wavelengths

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In a double-slit experiment the angular width of a fringe is found to be 0.2° on a screen placed 1 m away. The wavelength of light used is 600 nm. What will be the angular width of the fringe if the entire experimental apparatus is immersed in water? Take refractive index of water to be

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(i) In a double slit experiment using ight of wavelength 600 nm, the angular width of the fringe formed on a distant screen is 0.1°. Find the spacing between the two slits.(ii) Linght of wavelength `5000A^o` propagating in air gets partly reflected from the surface of water. How will the wavelengths and frequencies of the reflected and refracted light be

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(i) Using Huygens' construction of secondary wavelets explain how a diffraction pattern is obtained on a screen due to a narrow slit on which a monochromatic beam of light is incident normally.(ii) Show that the angular width of the irst diffraction fringe is half that of the central fringe.(iii) Explain why the maxima at `theta=(n+1/2)lambda/a` become weaker and weaker with increasing

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A beam of light consisting of two wavelengths 560 nm and 420 nm is used to obtain interference fringes in a Young's double slit experiment. Find the least distance from the central maximum, where the bright fringes, due to both the wavelengths coincide. The distance between the two slits is 4.0 mm and the screen is at a distance of 1.0 m from the

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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