JEE Main & Advanced Physics Wave Optics / तरंग प्रकाशिकी Question Bank

done Critical Thinking Total Questions - 63

• question_answer1)
  A ray of light of intensity I is incident on a parallel glass-slab at a point A as shown in fig. It undergoes partial reflection and refraction. At each reflection 25% of incident energy is reflected. The rays AB and A'B' undergo interference. The ratio \[{{I}_{\max }}/{{I}_{\min }}\] is                                                                [IIT 1990]
  A)
             4 : 1                                           done clear
  B)
             8 : 1 done clear
  C)
             7 : 1                                           done clear
  D)
             49 : 1 done clear
  View Solution play_arrow

• question_answer2)
  A thin slice is cut out of a glass cylinder along a plane parallel to its axis. The slice is placed on a flat glass plate as shown. The observed interference fringes from this combination shall be                                     [IIT-JEE (Screening)1999]
  A)
             Straight done clear
  B)
             Circular done clear
  C)
             Equally spaced done clear
  D)
             Having fringe spacing which increases as we go outwards done clear
  View Solution play_arrow

• question_answer3)
  In the adjacent diagram, CP represents a wavefront and AO & BP, the corresponding two rays. Find the condition on q for constructive interference at P between the ray BP and reflected ray OP                                [IIT-JEE (Screening) 2003]
  A)
             cosq = 3l/2d done clear
  B)
             cosq = l/4d done clear
  C)
             secq ? cosq = l/d done clear
  D)
             secq ? cosq = 4l/d done clear
  View Solution play_arrow

• question_answer4)
  In Young's double slit experiment, if monochromatic light is replaced by white light [AIIMS 2001; Kerala PET 2000; KCET 2004]
  A)
             All bright fringes become white done clear
  B)
             All bright fringes have colours between violet and red done clear
  C)
             Only the central fringe is white, all other fringes are coloured done clear
  D)
             No fringes are observed done clear
  View Solution play_arrow

• question_answer5)
  In Young's double slit experiment, if the two slits are illuminated with separate sources, no interference pattern is observed because
  A)
             There will be no constant phase difference between the two waves done clear
  B)
             The wavelengths are not equal done clear
  C)
             The amplitudes are not equal done clear
  D)
             None of the above done clear
  View Solution play_arrow

• question_answer6)
  In Young's double slit experiment, white light is used. The separation between the slits is b. The screen is at a distance d (d>> b) from the slits. Some wavelengths are missing exactly in front of one slit. These wavelengths are [IIT 1984; AIIMS 1995]
  A)
             \[\lambda =\frac{{{b}^{2}}}{d}\]                                      done clear
  B)
             \[\lambda =\frac{2{{b}^{2}}}{d}\] done clear
  C)
             \[\lambda =\frac{{{b}^{2}}}{3d}\]                                    done clear
  D)
             \[\lambda =\frac{2{{b}^{2}}}{3d}\] done clear
  View Solution play_arrow

• question_answer7)
  In a Young's double slit experiment the source S and the two slits A and B are vertical with slit A above slit B. The fringes are observed on a vertical screen K. The optical path length from S to B is increased very slightly (by introducing a transparent material of higher refractive index) and the optical path length from S to A is not changed, as a result the fringe system on K moves                                                        [NCERT 1984]
  A)
             Vertically downwards slightly done clear
  B)
             Vertically upwards slightly done clear
  C)
             Horizontally, slightly to the left done clear
  D)
             Horizontally, slightly to the right done clear
  View Solution play_arrow

• question_answer8)
  In an interference arrangement similar to Young's double slit experiment, the slits S1 and S2 are illuminated with coherent microwave sources each of frequency 106 Hz. The sources are synchronized to have zero phase difference. The slits are separated by distance d = 150 m. The intensity I\[(\theta )\]is measured as a function ofq, where q is defined as shown. If I0 is maximum intensity, then \[I(\theta )\] for \[0\le \theta \le {{90}^{o}}\]is given by                                                    [IIT 1995]
  A)
    \[I(\theta )={{I}_{0}}\]for \[\theta ={{0}^{o}}\]                  done clear
  B)
             \[I(\theta )={{I}_{0}}/2\]for \[\theta ={{30}^{o}}\] done clear
  C)
             \[I(\theta )={{I}_{0}}/4\]for \[\theta ={{90}^{o}}\] done clear
  D)
             \[I(\theta )\] is constant for all values of q done clear
  View Solution play_arrow

• question_answer9)
  In the Young's double slit experiment, if the phase difference between the two waves interfering at a point is f, the intensity at that point can be expressed by the expression [MP PET 1998; MP PMT 2003]
  A)
             \[I=\sqrt{{{A}^{2}}+{{B}^{2}}{{\cos }^{2}}\varphi }\]             done clear
  B)
             \[I=\frac{A}{B}\cos \varphi \] done clear
  C)
             \[I=A+B\cos \frac{\varphi }{2}\]                                       done clear
  D)
             \[I=A+B\cos \varphi \] Where A and B depend upon the amplitudes of the two waves. done clear
  View Solution play_arrow

• question_answer10)
  Figure here shows P and Q as two equally intense coherent sources emitting radiations of wavelength 20 m. The separation PQ is 5.0 m and phase of P is ahead of the phase of Q by 90o. A, B and C are three distant points of observation equidistant from the mid-point of PQ. The intensity of radiations at A, B, C will bear the ratio [NSEP 1994]
  A)
             0 : 1 : 4 done clear
  B)
             4 : 1 : 0 done clear
  C)
             0 : 1 : 2 done clear
  D)
             2 : 1 : 0 done clear
  View Solution play_arrow

• question_answer11)
  In Young's double slit experiment, the intensity on the screen at a point where path difference is l is K. What will be the intensity at the point where path difference is \[\lambda /4\] [RPET 1996]
  A)
             \[\frac{K}{4}\]                      done clear
  B)
             \[\frac{K}{2}\] done clear
  C)
             K     done clear
  D)
             Zero done clear
  View Solution play_arrow

• question_answer12)
  When one of the slits of Young?s experiment is covered with a transparent sheet of thickness 4.8 mm, the central fringe shifts to a position originally occupied by the 30th bright fringe. What should be the thickness  of the sheet if the central fringe has to shift to the position occupied by 20th bright fringe                                  [KCET 2002]
  A)
             3.8 mm                                    done clear
  B)
             1.6 mm done clear
  C)
             7.6 mm                                    done clear
  D)
             3.2 mm done clear
  View Solution play_arrow

• question_answer13)
  In the ideal double-slit experiment, when a glass-plate (refractive index 1.5) of thickness t is introduced in the path of one of the interfering beams (wavelength l), the intensity at the position where the central maximum occurred previously remains unchanged. The minimum thickness of the glass-plate is                              [IIT-JEE (Screening) 2002]
  A)
             2l   done clear
  B)
             \[\frac{2\lambda }{3}\] done clear
  C)
             \[\frac{\lambda }{3}\]       done clear
  D)
             l done clear
  View Solution play_arrow

• question_answer14)
  The time period of rotation of the sun is 25 days and its radius is\[7\times {{10}^{8}}m\]. The Doppler shift for the light of wavelength\[6000\,\,{AA}\]emitted from the surface of the sun will be                                                              [MP PMT 1994]
  A)
  \[0.04\,\,{AA}\]                 done clear
  B)
  \[0.40\,\,{AA}\] done clear
  C)
  \[4.00\,\,{AA}\] done clear
  D)
  \[40.0\,\,{AA}\] done clear
  View Solution play_arrow

• question_answer15)
  In hydrogen spectrum the wavelength of \[{{H}_{\alpha }}\] line is 656 nm whereas in the spectrum of a distant galaxy, \[{{H}_{\alpha }}\] line wavelength is 706 nm. Estimated speed of the galaxy with respect to earth is       [IIT-JEE 1999; UPSEAT 2003]
  A)
             \[2\times {{10}^{8}}m/s\]       done clear
  B)
             \[2\times {{10}^{7}}m/s\] done clear
  C)
             \[2\times {{10}^{6}}m/s\]       done clear
  D)
             \[2\times {{10}^{5}}m/s\] done clear
  View Solution play_arrow

• question_answer16)
  A rocket is going towards moon with a speed v. The astronaut in the rocket sends signals of frequency \[\nu \] towards the moon and receives them back on reflection from the moon. What will be the frequency of the signal received by the astronaut (Take v<<c)                             [RPMT 1996; DPMT 2000]
  A)
             \[\frac{c}{c-v}\nu \]           done clear
  B)
             \[\frac{c}{c-2v}\nu \] done clear
  C)
             \[\frac{2v}{c}\nu \]            done clear
  D)
             \[\frac{2c}{v}\nu \] done clear
  View Solution play_arrow

• question_answer17)
  The periodic time of rotation of a certain star is 22 days and its radius is 7 ' 108 metres. If the wavelength of light emitted by its surface be\[4320\,\,{AA}\], the Doppler shift will be (1 day = 86400 sec)                                         [MP PET 2001]
  A)
  \[0.033\,\,{AA}\] done clear
  B)
  \[0.33\,\,{AA}\] done clear
  C)
  \[3.3\,\,{AA}\]                    done clear
  D)
  \[33\,\,{AA}\] done clear
  View Solution play_arrow

• question_answer18)
  In a two slit experiment with monochromatic light fringes are obtained on a screen placed at some distance from the sits. If the screen is moved by \[5\times {{10}^{-2}}m\] towards the slits, the change in fringe width is\[3\times {{10}^{-5}}m\]. If separation between the slits is \[{{10}^{-3}}m\], the wavelength of light used is [Roorkee 1992]
  A)
  \[6000\,\,{AA}\] done clear
  B)
  \[5000\,\,{AA}\] done clear
  C)
  \[3000\,\,{AA}\]                done clear
  D)
  \[4500\,\,{AA}\] done clear
  View Solution play_arrow

• question_answer19)
  In the figure is shown Young?s double slit experiment. Q is the position of the first bright fringe on the right side of O. P is the 11th fringe on the other side, as measured from Q. If the wavelength of the light used is \[6000\times {{10}^{-10}}m\], then \[{{S}_{1}}B\] will be equal to                                                                          [CPMT 1986, 92]
  A)
             \[6\times {{10}^{-6}}m\] done clear
  B)
             \[6.6\times {{10}^{-6}}m\] done clear
  C)
             \[3.138\times {{10}^{-7}}m\] done clear
  D)
             \[3.144\times {{10}^{-7}}m\] done clear
  View Solution play_arrow

• question_answer20)
  In Young?s double slit experiment, the two slits act as coherent sources of equal amplitude A and wavelengthl. In another experiment with the same set up the two slits are of equal amplitude A and wavelength l but are incoherent. The ratio of the intensity of light at the mid-point of the screen in the first case to that in the second case is [IIT-JEE 1986; RPMT 2002]
  A)
             1 : 2                                           done clear
  B)
             2 : 1 done clear
  C)
             4 : 1                                           done clear
  D)
             1 : 1 done clear
  View Solution play_arrow

• question_answer21)
  Four light waves are represented by (i) y = a1 sinw t                                 (ii) \[y={{a}_{2}}\sin (\omega \,t+\varphi )\] (iii) \[y={{a}_{1}}\sin 2\omega \,t\]    (iv) \[y={{a}_{2}}\sin 2(\,\omega \,t+\varphi )\] Interference fringes may be observed due to superposition of
  A)
             (i) and (ii)                                done clear
  B)
             (i) and (iii) done clear
  C)
             (ii) and (iv)                             done clear
  D)
             (iii) and (iv) done clear
  View Solution play_arrow

• question_answer22)
  In Young's double slit experiment the y-coordinates of central maxima and 10th maxima are 2 cm and 5 cm respectively. When the YDSE apparatus is immersed in a liquid of refractive index 1.5 the corresponding y-coordinates will be
  A)
             2 cm, 7.5 cm done clear
  B)
             3 cm, 6 cm done clear
  C)
             2 cm, 4 cm done clear
  D)
             4/3 cm, 10/3 cm done clear
  View Solution play_arrow

• question_answer23)
  The maximum intensity in Young's double slit experiment is I0. Distance between the slits is d = 5l, where l is the wavelength of monochromatic light used in the experiment. What will be the intensity of light in front of one of the slits on a screen at a distance \[D=10\,d\]
  A)
             \[\frac{{{I}_{0}}}{2}\]         done clear
  B)
             \[\frac{3}{4}{{I}_{0}}\] done clear
  C)
             I0     done clear
  D)
             \[\frac{{{I}_{0}}}{4}\] done clear
  View Solution play_arrow

• question_answer24)
  A monochromatic beam of light falls on YDSE apparatus at some angle (sayq) as shown in figure. A thin sheet of glass is inserted in front of the lower slit S2. The central bright fringe (path difference = 0) will be obtained
  A)
             At O done clear
  B)
             Above O done clear
  C)
             Below O done clear
  D)
             Anywhere depending on angleq, thickness of plate t and refractive index of glass m done clear
  View Solution play_arrow

• question_answer25)
  In Young's double slit experiment how many maxima?s can be obtained on a screen (including the central maximum) on both sides of the central fringe if \[\lambda =2000\,{AA}\] and \[d=7000\,{AA}\]
  A)
  12   done clear
  B)
  7 done clear
  C)
  18   done clear
  D)
  4 done clear
  View Solution play_arrow

• question_answer26)
  In a Young's double slit experiment, the slits are 2 mm apart and are illuminated with a mixture of two wavelength \[{{\lambda }_{0}}=750nm\] and \[\lambda =900nm\]. The minimum distance from the common central bright fringe on a screen 2m  from the slits where a bright fringe from one interference pattern coincides with a bright fringe from the other is
  A)
             1.5 mm                                    done clear
  B)
             3 mm done clear
  C)
             4.5 mm                                    done clear
  D)
             6 mm done clear
  View Solution play_arrow

• question_answer27)
  A flake of glass (refractive index 1.5) is placed over one of the openings of a double slit apparatus. The interference pattern displaces itself through seven successive maxima towards the side where the flake is placed. if wavelength of the diffracted light is \[\lambda =600nm\], then the thickness of the flake is
  A)
             2100 nm                                  done clear
  B)
             4200 nm done clear
  C)
             8400 nm                                  done clear
  D)
             None of these done clear
  View Solution play_arrow

• question_answer28)
  Two ideal slits S1 and S2 are at a distance d apart, and illuminated by light of wavelength l passing through an ideal source slit S placed on the line through S2 as shown. The distance between the planes of slits and the source slit is D. A screen is held at a distance D from the plane of the slits. The minimum value of d for which there is darkness at O is
  A)
             \[\sqrt{\frac{3\lambda D}{2}}\] done clear
  B)
             \[\sqrt{\lambda D}\] done clear
  C)
             \[\sqrt{\frac{\lambda D}{2}}\] done clear
  D)
             \[\sqrt{3\lambda D}\] done clear
  View Solution play_arrow

• question_answer29)
  In a double slit arrangement fringes are produced using light of wavelength\[4800\,\,{AA}\]. One slit is covered by a thin plate of glass of refractive index 1.4 and the other with another glass plate of same thickness but of refractive index 1.7. By doing so the central bright shifts to original fifth bright fringe from centre. Thickness of glass plate is
  A)
  8 mm                                         done clear
  B)
  6 mm done clear
  C)
  4 mm                                         done clear
  D)
  10 mm done clear
  View Solution play_arrow

• question_answer30)
  Two point sources X and Y emit waves of same frequency and speed but Y lags in phase behind X by 2pl radian. If there is a maximum in direction D the distance XO using n as an integer is given by
  A)
             \[\frac{\lambda }{2}(n-l)\] done clear
  B)
             \[\lambda (n+l)\] done clear
  C)
             \[\frac{\lambda }{2}(n+l)\] done clear
  D)
             \[\lambda (n-l)\] done clear
  View Solution play_arrow

• question_answer31)
  A beam with wavelength l falls on a stack of partially reflecting planes with separation d. The angle q that the beam should make with the planes so that the beams reflected from successive planes may interfere constructively is (where n =1, 2,??)
  A)
             \[{{\sin }^{-1}}\left( \frac{n\lambda }{d} \right)\] done clear
  B)
             \[{{\tan }^{-1}}\left( \frac{n\lambda }{d} \right)\] done clear
  C)
             \[{{\sin }^{-1}}\left( \frac{n\lambda }{2d} \right)\] done clear
  D)
             \[{{\cos }^{-1}}\left( \frac{n\lambda }{2d} \right)\] done clear
  View Solution play_arrow

• question_answer32)
  Two coherent sources separated by distance\[d\]are radiating in phase having wavelengthl. A detector moves in a big circle around the  two sources in the plane of the two sources. The angular position of n = 4 interference maxima is given as
  A)
             \[{{\sin }^{-1}}\frac{n\lambda }{d}\] done clear
  B)
             \[{{\cos }^{-1}}\frac{4\lambda }{d}\] done clear
  C)
             \[{{\tan }^{-1}}\frac{d}{4\lambda }\] done clear
  D)
             \[{{\cos }^{-1}}\frac{\lambda }{4d}\] done clear
  View Solution play_arrow

• question_answer33)
  Two coherent sources S1 and S2 are separated by a distance four times the wavelength l of the source. The sources lie along y axis whereas a detector moves along + x axis. Leaving the origin and far off points the number of points where maxima are observed is
  A)
             2     done clear
  B)
             3 done clear
  C)
             4     done clear
  D)
             5 done clear
  View Solution play_arrow

• question_answer34)
  A circular disc is placed in front of a narrow source. When the point of observation is at a distance of 1 meter from the disc, then the disc covers first HPZ. The intensity at this point is I0. The intensity at a point distance 25 cm from the disc will be
  A)
             \[{{I}_{1}}=0.531{{I}_{0}}\]     done clear
  B)
             \[{{I}_{1}}=0.053{{I}_{0}}\] done clear
  C)
             \[{{I}_{1}}=53{{I}_{0}}\]    done clear
  D)
             \[{{I}_{1}}=5.03{{I}_{0}}\] done clear
  View Solution play_arrow

• question_answer35)
  A wavefront presents one, two and three HPZ at points A, B and C respectively. If the ratio of consecutive amplitudes of HPZ is 4 : 3, then the ratio of resultant intensities at these point will be
  A)
             169 : 16  : 256                         done clear
  B)
             256 : 16 : 169 done clear
  C)
             256 : 16 : 196                          done clear
  D)
             256 : 196 : 16 done clear
  View Solution play_arrow

• question_answer36)
  A circular disc is placed in front of a narrow source. When the point of observation is 2 m from the disc, then it covers first HPZ. The intensity at this point is I. When the point of observation is 25 cm from the disc then intensity will be
  A)
             \[{{\left( \frac{{{R}_{6}}}{{{R}_{2}}} \right)}^{2}}I\]  done clear
  B)
             \[{{\left( \frac{{{R}_{7}}}{{{R}_{2}}} \right)}^{2}}I\] done clear
  C)
             \[{{\left( \frac{{{R}_{8}}}{{{R}_{2}}} \right)}^{2}}I\]  done clear
  D)
             \[{{\left( \frac{{{R}_{9}}}{{{R}_{2}}} \right)}^{2}}I\] done clear
  View Solution play_arrow

• question_answer37)
  In a single slit diffraction of light of wavelength l by a slit of width e, the size of the central maximum on a screen at a distance b is
  A)
             \[2b\lambda +e\]               done clear
  B)
             \[\frac{2b\lambda }{e}\] done clear
  C)
             \[\frac{2b\lambda }{e}+e\]    done clear
  D)
             \[\frac{2b\lambda }{e}-e\] done clear
  View Solution play_arrow

• question_answer38)
  Angular width of central maxima in the Fraunhoffer diffraction pattern of a slit is measured. The slit is illuminated by light of wavelength \[6000\,{AA}\]. When the slit is illuminated by light of another wavelength, the angular width decreases by 30%. The wavelength of this light will be
  A)
  \[6000\,\,{AA}\]                done clear
  B)
  \[4200\,\,{AA}\] done clear
  C)
  \[3000\,\,{AA}\]                done clear
  D)
  \[1800\,\,{AA}\] done clear
  View Solution play_arrow

• question_answer39)
  In a single slit diffraction experiment first minimum for red light (660 nm) coincides with first maximum of some other wavelength l'. The value of l' is
  A)
  \[4400\,\,{AA}\] done clear
  B)
  \[6600\,\,{AA}\] done clear
  C)
  \[2000\,\,{AA}\] done clear
  D)
  \[3500\,\,{AA}\] done clear
  View Solution play_arrow

• question_answer40)
  The ratio of intensities of consecutive maxima in the diffraction pattern due to a single slit is
  A)
             1 : 4 : 9                                     done clear
  B)
             1 : 2 : 3 done clear
  C)
             \[1\,:\frac{4}{9\,{{\pi }^{2}}}:\frac{4}{25\,{{\pi }^{2}}}\]       done clear
  D)
             \[1:\frac{1}{{{\pi }^{2}}}:\frac{9}{{{\pi }^{2}}}\] done clear
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• question_answer41)
  Light is incident normally on a diffraction grating through which the first order diffraction is seen at 32o. The second order diffraction will be seen at
  A)
             48o done clear
  B)
             64o done clear
  C)
             80o done clear
  D)
             There is no second order diffraction in this case done clear
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• question_answer42)
  White light may be considered to be a mixture of waves with l ranging between\[3900\,\,{AA}\]and\[7800\,\,{AA}\]. An oil film of thickness\[10,000\,\,{AA}\]is examined normally by reflected light. If m = 1.4, then the film appears bright for
  A)
  \[4308\,\,{AA},\,\,5091\,\,{AA},\,\,6222\,\,{AA}\] done clear
  B)
  \[4000\,\,{AA},\,\,5091\,\,{AA},\,\,5600\,\,{AA}\] done clear
  C)
  \[4667\,\,{AA},\,\,6222\,\,{AA},7000\,\,{AA}\] done clear
  D)
  \[4000\,\,{AA},\,\,4667\,\,{AA},\,\,5600\,\,{AA},\,\,7000\,\,{AA}\] done clear
  View Solution play_arrow

• question_answer43)
  Among the two interfering monochromatic sources A and B; A is ahead of B in phase by 66°. If the observation be taken from point P, such that PB ? PA = l/4. Then the phase difference between the waves from A and B reaching P is
  A)
             156°                                          done clear
  B)
             140° done clear
  C)
             136°                                          done clear
  D)
             126° done clear
  View Solution play_arrow

• question_answer44)
  The ratio of the intensity at the centre of a bright fringe to the intensity at a point one-quarter of the distance between two fringe from the centre is
  A)
             2     done clear
  B)
             1/2 done clear
  C)
             4     done clear
  D)
             16 done clear
  View Solution play_arrow

• question_answer45)
  A parallel plate capacitor of plate separation 2 mm is connected in an electric circuit having source voltage 400 V. if the plate area is 60 cm2, then the value of displacement current for \[{{10}^{-6}}\,\sec \] will be
  A)
             1.062 amp                              done clear
  B)
             \[1.062\times {{10}^{-2}}\]amp done clear
  C)
             \[1.062\times {{10}^{-3}}\]amp                                        done clear
  D)
             \[1.062\times {{10}^{-4}}\]amp done clear
  View Solution play_arrow

• question_answer46)
  A long straight wire of resistance R, radius a and length l carries a constant current I. The Poynting vector for the wire will be
  A)
             \[\frac{IR}{2\pi al}\]           done clear
  B)
             \[\frac{I{{R}^{2}}}{al}\] done clear
  C)
             \[\frac{{{I}^{2}}R}{al}\]     done clear
  D)
             \[\frac{{{I}^{2}}R}{2\pi al}\] done clear
  View Solution play_arrow

• question_answer47)
  In an electromagnetic wave, the amplitude of electric field is 1 V/m. the frequency of wave is \[5\times {{10}^{14}}\,Hz\]. The wave is propagating along z-axis. The average energy density of electric field, in Joule/m3, will be
  A)
             \[1.1\times {{10}^{-11}}\]       done clear
  B)
             \[2.2\times {{10}^{-12}}\] done clear
  C)
             \[3.3\times {{10}^{-13}}\]       done clear
  D)
             \[4.4\times {{10}^{-14}}\] done clear
  View Solution play_arrow

• question_answer48)
  A laser beam can be focussed on an area equal to the square of its wavelength A He-Ne laser radiates energy at the rate of 1mW and its wavelength is 632.8 nm. The intensity of focussed beam will be
  A)
             \[1.5\times {{10}^{13}}\,W/{{m}^{2}}\]                        done clear
  B)
             \[2.5\times {{10}^{9}}\,W/{{m}^{2}}\] done clear
  C)
             \[3.5\times {{10}^{17}}\,W/{{m}^{2}}\]                        done clear
  D)
             None of these done clear
  View Solution play_arrow

• question_answer49)
  A lamp emits monochromatic green light uniformly in all directions. The lamp is 3% efficient in converting electrical power to electromagnetic waves and consumes 100W of power. The amplitude of the electric field associated with the electromagnetic radiation at a distance of 10m from the lamp will be
  A)
             1.34 V/m                                 done clear
  B)
             2.68 V/m done clear
  C)
             5.36 V/m                                 done clear
  D)
             9.37 V/m done clear
  View Solution play_arrow

• question_answer50)
  A point source of electromagnetic radiation has an average power output of 800 W. The maximum value of electric field at a distance 4.0 m from the source is
  A)
             64.7 V/m                                 done clear
  B)
             57.8 V/m done clear
  C)
             56.72 V/m                              done clear
  D)
             54.77 V/m done clear
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• question_answer51)
  A wave is propagating in a medium of electric dielectric constant 2 and relative magnetic permeability 50. The wave impedance of such a medium is
  A)
             5 W                                            done clear
  B)
             376.6 W done clear
  C)
             1883 W                                     done clear
  D)
             3776 W done clear
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• question_answer52)
  A plane electromagnetic wave of wave intensity 6 W/m2 strikes a small mirror area 40 cm2, held perpendicular to the approaching wave. The momentum transferred by the wave to the mirror each second will be 
  A)
             \[6.4\times {{10}^{-7}}kg-m/{{s}^{2}}\]                        done clear
  B)
             \[4.8\times {{10}^{-8}}kg-m/{{s}^{2}}\] done clear
  C)
             \[3.2\times {{10}^{-9}}kg-m/{{s}^{2}}\]                        done clear
  D)
             \[1.6\times {{10}^{-10}}kg-m/{{s}^{2}}\] done clear
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• question_answer53)
  Specific rotation of sugar solution is 0.01 SI units. 200\[kg{{m}^{-3}}\]of impure sugar solution is taken in a polarimeter tube of length 0.25m and an optical rotation of 0.4rad is observed. The percentage of purity of sugar is the sample is [KCET 2004]
  A)
             80%                                           done clear
  B)
             89% done clear
  C)
             11%                                           done clear
  D)
             20% done clear
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• question_answer54)
  A 20 cm length of a certain solution causes right-handed rotation of 38°. A 30cm length of another solution causes left-handed rotation of 24°. The optical rotation caused by 30cm length of a mixture of the above solutions in the volume ratio 1 : 2 is                                                             [KCET 2001]
  A)
             Left handed rotation of 14° done clear
  B)
             Right handed rotation of 14° done clear
  C)
             Left handed rotation of 3° done clear
  D)
             Right handed rotation of 3° done clear
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• question_answer55)
  A beam of natural light falls on a system of 6 polaroids, which are arranged in succession such that each polaroid is turned through 30° with respect to the preceding one. The  percentage of incident intensity that passes through the system will be
  A)
             100%                                        done clear
  B)
             50% done clear
  C)
             30%                                           done clear
  D)
             12% done clear
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• question_answer56)
  A beam of plane polarized light falls normally on a polarizer of cross sectional area \[3\times {{10}^{-4}}{{m}^{2}}\]. Flux of energy of incident ray in 10?3 W. The polarizer rotates with an angular frequency of 31.4 rad/sec. The energy of light passing through the polarizer per revolution will be
  A)
             10?4 Joule                                done clear
  B)
             10?3 Joule done clear
  C)
             10?2 Joule                                done clear
  D)
             10?1 Joule done clear
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• question_answer57)
  In a YDSE bi-chromatic light of wavelengths 400 nm and 560 nm are used. The distance between the slits is 0.1 mm and the distance between the plane of the slits and the screen is 1m. The minimum distance between two successive regions of complete darkness is [IIT JEE (Screening) 2004]
  A)
             4 mm                                        done clear
  B)
             5.6 mm done clear
  C)
             14 mm                                     done clear
  D)
             28 mm done clear
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• question_answer58)
  The maximum number of possible interference maxima for slit-separation equal to twice the wavelength in Young?s double-slit experiment is                                           [AIEEE 2004]
  A)
             Infinite                                    done clear
  B)
             Five done clear
  C)
             Three                                       done clear
  D)
             Zero done clear
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• question_answer59)
  The k line of singly ionised calcium has a wavelength of 393.3 nm as measured on earth. In the spectrum of one of the observed galaxies, this spectral line is located at 401.8 nm. The speed with which the galaxy is moving away from us, will be                                                                      [Pb. PET 2003]
  A)
             6480 km/s                              done clear
  B)
             3240 km/s done clear
  C)
             4240 km/sec                          done clear
  D)
              None of these done clear
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• question_answer60)
  A Young's double slit experiment uses a monochromatic source. The shape of the interference fringes formed on a screen is                                                                   [AIEEE 2005]
  A)
             Straight line                           done clear
  B)
             Parabola done clear
  C)
             Hyperbola                              done clear
  D)
             Circle done clear
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• question_answer61)
  If \[{{I}_{0}}\] is the intensity of the principal maximum in the single slit diffraction pattern, then what will be its intensity when the slit width is doubled                                                                   [AIEEE 2005]
  A)
  \[{{I}_{0}}\]                           done clear
  B)
  \[\frac{{{I}_{0}}}{2}\] done clear
  C)
  \[2{{I}_{0}}\]                         done clear
  D)
  \[4\,{{I}_{0}}\] done clear
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• question_answer62)
  In Young's double slit experiment intensity at a point is (1/4) of the maximum intensity. Angular position of this point is   [IIT-JEE (Screening) 2005]
  A)
             sin-1(l/d)                                done clear
  B)
             sin-1(l/2d) done clear
  C)
             sin-1(l/3d)                              done clear
  D)
             sin-1(l/4d) done clear
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• question_answer63)
  A beam of electron is used in an YDSE experiment. The slit width is d. When the velocity of electron is increased, then  [IIT-JEE (Screening) 2005]
  A)
             No interference is observed done clear
  B)
             Fringe width increases done clear
  C)
             Fringe width decreases done clear
  D)
             Fringe width remains same done clear
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