Tiêu đề WAVE OPTICS.pdf ✅

CHAPTER WAVE OPTICS 10 Exercise 1: NCERT Based Topic-wise MCQs 10.1 INTRODUCTION 1. To explain the propagation of light through vaccum, initially it was assumed that, medium through which light waves travel is NCERT Page-352 / N-255 (a) metal only (c) liquid only (b) luminiferous ether (d) solid 2. Newton's corpuscular theory could not explain the phenomenon for NCERT Page-352 / N-256 (a) reflection (b) refraction (c) diffraction (d) rectilinear propagation 10.2 HUYGENS PRINCIPLE 3. Wavefront is the locus of all points, where the particles of the medium vibrate with the same (a) phase NCERT Page-353 / N-257 (b) amplitude (c) frequency (d) period 4. Huygen's concept of secondary wave NCERT Page-354 / N-257 (a) allows us to find the focal length of a thick lens (b) is a geometrical method to find a wavefront (c) is used to determine the velocity of light (d) is used to explain polarisation 5. The phenomena which is not explained by Huygen's construction of wavefront is NCERT/ Page-354 / N-257 (a) reflection (b) diffraction (c) refraction (d) origin of spectra 6. When light suffers reflection at the interface between water and glass, the change of phase in the reflected wave is (a) zero NCERT Page-356/ N-257 (b) π (c) π/2 (d) 2π 7. Which of the following is correct for light diverging from a point source? NCERT/ Page-353 / N-257 (a) The intensity decreases in proportion for the distance squared.
(b) The wavefront is parabolic. (c) The intensity at the wavelingth does depend of the distance. (d) None of these. 10.3 REFRACTION AND REFLECTION OF PLANE WAVES USING HUYGENS PRINCIPLE 8. A plane wave passes through a convex lens. The geometrical shape of the wavefront that emerges is (a) plane NCERT Page-358 / N-261 (b) diverging spherical (c) converging spherical (d) None of these 9. A wavefront AB passing through a system C emerges as DE. The system C could be NCERT Page-358 / N-261 (a) a slit (b) a biprism (c) a prism (d) a glass slab 10. Figure shows wavefront P passing through two systems A and B and emerging as Q and then as R. The system A and B could, respectively, be NCERT Page-358 / N-261 (a) a prism and a convergent lens (b) a convergent lens and a prism (c) a divergent lens and a prism (d) a convergent lens and a divergent lens 11. Spherical wavefronts, emanating from a point source, strike a plane reflecting surface. What will happen to these wavefronts, immediately after reflection? NCERT Page-358 / N-261 (a) They will remain spherical with the same curvature, both in magnitude and sign. (b) They will become plane wave fronts. (c) They will remain spherical, with the same curvature, but sign of curvature reversed. (d) They will remain spherical, but with different curvature, both in magnitude and sign. 10.4 COHERENT AND INCOHERENT ADDITION OF WAVES 12. Two sources of light are said to be coherent, when they give light waves of same NCERT Page-360 / N-264 (a) amplitude and phase
(b) wavelength and constant phase difference (c) intensity and wavelength (d) phase and speed 13. The interfering fringes formed by a thin oil film on water are seen in yellow light of sodium lamp. We find the fringes NCERT Page-365 / N-264 (a) coloured (b) black and white (c) yellow and black (d) coloured without yellow 14. The light waves from two coherent sources have same intensity I1 = I2 = I0. In interference pattern the intensity of light at minima is zero. What will be the intensity of light at maxima? NCERT Page-365/ N-264 (a) I0 (b) 2I0 (c) 5I0 (d) 4I0 15. Two beams of light of intensity I1 and I2 interfere to give an interference pattern. If the ratio of maximum intensity to that of minimum intensity is 25/9, then I1/I2 is NCERT Page-365/ N-264 (a) 5/3 (b) 4 (c) 81/625 (d) 16 16. The colour of bright fringe nearest to central achromatic fringe in the interference pattern with white light will be (a) violet NCERT Page-364 / N-265, 266 (b) red (c) green (d) yellow 17. Two coherent monochromatic light beams of intensities I and 4I are superposed. The maximum and minimum possible intensities in the resulting beam are NCERT Page-362/ N-264 (a) 5I and I (b) 5I and 3I (c) 9I and I (d) 9I and 3I 18. Two coherent sources of light interfere. The intensity ratio of two sources is 1: 4. For this interference pattern if the value of Imax+Imin Imax−Imin is equal to 2α+1 β+3 , then α β will be: NCERT Page-362/ N-264 (a) 1.5 (b) 2 (c) 0.5 (d) 1 19. A point p is situated 90.50 and 90.58cm away from two coherent sources. The nature of illumination of the point ' p ' if the wavelength of light is 4000Å, is NCERT/ Page-361/ N-263 (a) bright (b) dark (c) neither bright nor dark (d) none of these 20. The path difference between two interfering waves at a point on screen is 171.5 times the wavelength. If the path difference is 0.01029cm. Find the wavelength. NCERT Page-361/ N-264 (a) 6000 × 10−10cm
(b) 6000Å (c) 6000 × 10−8mm (d) None of these 21. Two coherent sources of sound, S1 and S2, produce sound waves of the same wavelength, λ = 1m, in phase. S1 and S2 are placed 1.5m apart (see fig.). A listener, located at L, directly in front of S2 finds that the intensity is at a minimum when he is 2m away from S2. The listener moves away from S1, keeping his distance from S2 fixed. The adjacent maximum of intensity is observed when the listener is at a distance d from S1. Then, d is : (a) 12m NCERT/ Page-362/ N-263 (b) 5m (c) 2m (d) 3m 22. Find the minimum thickness of a film which will strongly reflect the light of wavelength 598nm. The refractive index of the material of the film is 1.25 . NCERT Page-362/N-263 (a) 118nm (b) 120nm (c) 218m (d) 225mm 23. Two light waves superimposing at the mid-point of the screen are coming from coherent sources of light with phase difference 3π rad. Their amplitudes are 1cm each. The resultant amplitude at the given point will be. (a) 5cm NCERT Page-362/N-263 (b) 3cm (c) 2cm (d) zero 24. The path difference between two wavefronts emitted by coherent sources of wavelength 5460Å is 2.1 micron. The phase difference between the wavefronts at that point is NCERT Page-362/ N-263 (a) 7.692 (b) 7.692π (c) 7.692 π (d) 7.692 3π 25. A thin film of soap solution (μs = 1.4) lies on the top of a glass plate (μg = 1.5). When visible light is incident almost normal to the plate, two adjacent reflection maxima are observed at two wavelengths 420 and 630nm. The minimum thickness of the soap solution is NCERT Page-362/ N-264 (a) 420nm (b) 450nm