Wave Optics PYQs Set 6 (PDF)

Set 6 of 9 · Questions 151-180 of 243

In the print window choose “Save as PDF”. The file prints without a web address or date line.

Mere Teacher · Previous Year Questions NEET Physics · Wave Optics · Set 6 (Q151-180)
Scan or visit mereteacher.com for free PYQ practice, timed CBT tests, step-by-step solutions and BroBot AI. Answers and solutions are free with a sign-up.
151. $Light of wavelength ' ' is incident on a slit of width ' ' 'The resulting diffraction pattern is observed on a screen at a distance ' '. The linear width of the principal maximum is then equal to the width of the slit if equals$ (1) $\frac{d}{λ}$ (2) $\frac{d ^{2}}{2 λ}$ (3) $\frac{2 λ}{d}$ (4) $\frac{2 λ ^{2}}{d}$ 152. $In a Young's double slit experiment, m^{th} order and n^{th} order of bright fringes are formed at point P on a distant screen, if monochromatic source of wavelength 400 nm and 600 nm are used respectively. The minimum value of m and n are respectively$ (1) $4,6$ (2) $3,2$ (3) $2,3$ (4) $4,2$ 153. $When a Compact Disc (CD) is illuminated by small source of white light, coloured bands are observed. This is due to$ (1) $interference$ (2) $scattering$ (3) $reflection$ (4) $diffraction.$ 154. $The width of one of the two slits in a Young's double slit experiment is 4 times that of the other slit. The ratio of the maximum of the minimum intensity in the interference pattern is:$ (1) $1 : 1$ (2) $4 : 1$ (3) $9 : 1$ (4) $16 : 1$ 155. $In Young's double slit experiment, fringes of width β are produced on a screen kept at a distance of 1 m from the slit. When the screen is moved away by 5 \times 10^{- 2} m, fringe width changes by 3 \times 10^{- 5} m . The separation between the slits is 1 \times 10^{- 3} m . The wavelength of the light used is nm .$ (1) $500$ (2) $600$ (3) $700$ (4) $400$ 156. $White light reflected from a soap film (Refractive index ) has a maxima at and a minima at with no minimum in between. Then the thickness of the film is .$ (1) $1$ (2) $2$ (3) $3$ (4) $4$ 157. $In biprism experiment, the distance between source and eyepiece is 1.2 m, the distance between two virtual sources is 0.84 mm . Then the wavelength of light used if eyepiece is to be moved transversely through a distance of 2.799 cm to shift 30 fringes is$ (1) $6533Å$ (2) $6531Å$ (3) $6535Å$ (4) $6351Å$ 158. $If numerical aperture of a microscope is increased, then its$ (1) $resolving power remains constant.$ (2) $resolving power becomes zero.$ (3) $limit of resolution is decreased.$ (4) $limit of resolution is increased.$ 159. $In Young's double slit experiment, light from two identical sources are superimposing on a screen. The path difference between the two lights reaching at a point on the screen is \frac{7 λ}{4} . The ratio of intensity of fringe at this point with respect to the maximum intensity of the fringe is :$ (1) $½$ (2) $3/4$ (3) $1/3$ (4) $1/4$ 160. $What would be the angular separation between the consecutive bright fringes in Young's double slit experiment with blue-green light of wavelength 400 nm ? The separation between the slits is 0.001 m .$ (1) $4 \times 10^{- 4} rad$ (2) $3 \times 10^{- 4} rad$ (3) $2 \times 10^{- 4} rad$ (4) $1 \times 10^{- 4} rad$ 161. $In free space, an electromagnetic wave of 3 GHz of 3 GHz frequency strikes over the edge of an object of size \frac{λ}{100}, where λ is the wavelength of the wave in free space. The phenomenon, which happens there will be:$ (1) $Reflection$ (2) $Refraction$ (3) $Diffraction$ (4) $Scattering$ 162. $In a Young’s double slit experiment, the two slits act as coherent sources of waves of equal amplitude A and wavelength λ. In another experiment with the same arrangement the two slits are made to act as incoherent sources of waves of same amplitude and wavelength. If the intensity at the middle point of the screen in the first case is I_{1} and in the second case is I_{2}, then the ratio \frac{I _{1}}{I _{2}} is :$ (1) $2$ (2) $1$ (3) $0.5$ (4) $4$ 163. $Light from two coherent sources of the same amplitude A and wavelength λ illuminates the screen. The intensity of the central maximum is I_{0} . If the sources were incoherent, the intensity at the same point will be$ (1) $4 I_{0}$ (2) $2 I_{0}$ (3) $I_{0}$ (4) $I_{0} /2$ 164. $If the slit width is 2 mm and wavelength of light used is 4000Å, then Fresnel distance is nearly$ (1) $2 mm$ (2) $10 m$ (3) $20 km$ (4) $2 μ m$ 165. $In an interference experiment the ratio of amplitudes of coherent waves is \frac{a _{1}}{a _{2}} = \frac{1}{3} Theratio of maximum and minimum intensities of fringes will be:$ (1) $2$ (2) $18$ (3) $4$ (4) $9$ 166. $The distance of a point on the screen from two slits in biprism experiment is 1.8 \times 10^{- 5} m and 1.23 \times 10^{- 5} m . If wavelength of light used is 6000Å, the fringe formed at that point is$ (1) $10^{th} bright$ (2) $10^{th} dark$ (3) $9^{th} bright$ (4) $9^{th} dark$ 167. $In Young's double slit experiment, two wavelengths λ_{1} = 780 nm and λ_{2} = 520 nm are used to obtain interference fringes. If the n^{th} bright band due to λ_{1} coincides with (n + 1)^{th} bright band due to λ_{2}, then the value of n is$ (1) $4$ (2) $3$ (3) $2$ (4) $6$ 168. $The polarizing angle of glass is . A ray of light which is incident at this angle will have an angle of refraction as$ (1) $33^{\circ}$ (2) $38^{\circ}$ (3) $25^{\circ}$ (4) $43^{\circ}$ 169. $When a light ray incidents on the surface of a medium, the reflected ray is completely polarized. Then the angle between reflected and refracted rays is$ (1) $45^{\circ}$ (2) $90^{\circ}$ (3) $120^{\circ}$ (4) $180^{\circ}$ 170. $In Young’s double slits experiment, the position of 5^{t h} bright fringe from the central maximum is 5 cm. The distance between slits and screen is 1 m and wavelength of used monochromatic light is 600 nm. The separation between the slits is:$ (1) $60 μ m$ (2) $48 μ m$ (3) $12 μ m$ (4) $36 μ m$ 171. $Which of the following phenomena can not be explained by wave theory of light?$ (1) $Compton effect$ (2) $Refraction of light$ (3) $Reflection of light$ (4) $Diffraction of light$ 172. $Two light waves of intensities ' I_{1}' and ' I_{2}' having same frequency pass through same medium at a time in same direction and interfere. The sum of the minimum and maximum intensities is$ (1) $(I_{1} + I_{2})$ (2) $(I_{1} + I_{2})$ (3) $2 (I_{1} + I_{2})$ (4) $(I_{1} - I_{2})$ 173. $Two coherent light sources having intensity in the ratio 2 x produce an interference pattern. Then the value of \frac{I _{max} - I _{min}}{I _{max} + I _{min}} will be$ (1) $\frac{2 2 x}{x + 1}$ (2) $\frac{2 x}{2 x + 1} .$ (3) $\frac{2 2 x}{2 x + 1}$ (4) $\frac{2 x}{x + 1}$ 174. $Given below are two statements: Statement I: A plane wave after passing through prism remains as plane wave but passing through small pin hole may become spherical wave. Statement II: The curvature of a spherical wave emerging from a slit will increase for increasing slit width. In the light of the above statements, choose the correct answer from the options given below$ (1) $Both Statement I and Statement II are true$ (2) $Statement I is false but Statement II is true$ (3) $Both Statement I and Statement II are false$ (4) $Statement I is true but Statement II is false$ 175. $In a single slit experiment, the width of the slit is doubled. Which one of the following statements is correct?$ (1) $The intensity and angular width of the central maximum are unaffected.$ (2) $The intensity remains same and angular width becomes half.$ (3) $The intensity and angular width both are doubled.$ (4) $The intensity increases by a factor 4 and the angular width decreases by a factor of \frac{1}{2} .$ 176. $Using the expression 2d sin θ = λ, one calculates the values of d by measuring the corresponding angles θ in the range 0 to 90º. The wavelength λ is exactly knowns and the error in θ is constant for all values of θ. As θ increases from 0º :$ (1) $the absolute error in d remains constant.$ (2) $the absolute error in d increases.$ (3) $the fractional error in d remains constant.$ (4) $the fractional error in d decreases$ 177. $Which of the statements are correct with reference to single slit diffraction pattern? (i) Fringes are of unequal width(ii) Fringes are of equal width(iii) Light energy is conserved(iv) Intensities of all bright fringes are equal$ (1) $(i) and (iii)$ (2) $(i) and (iv)$ (3) $(ii) and (iv)$ (4) $(ii) and (iii)$ 178. $A single slit of width a is illuminated by a monochromatic light of wavelength 600 nm. The value of a for which first minimum appears at θ = 30° on the screen will be :$ (1) $1.2 μ m$ (2) $3 μ m$ (3) $1.8 μ m$ (4) $0.6 μ m$ 179. $Statement - 1 : On viewing the clear blue portion of the sky through a Calcite Crystal, the intensity of transmitted light varies as the crystal is rotated. Statement - 2 :The light coming from the sky is polarized due to scattering of sun light by particles in the atmosphere. The scattering is largest for blue light$ (1) $Statement-1 is true, statement-2 is false.$ (2) $Statement-1 is true, statement-2 is true, statement-2 is the correct explanation of statment-1$ (3) $Statement-1 is true, statement-2 is true, statement-2 is not the correct explanation of statement-1$ (4) $Statement-1 is false, statement-2 is true.$ 180. $Two coherent sources P and Q produce interference at point A on the screen where there is a dark band which is formed between 4^{th} bright band and 5^{th} bright band. Wavelength of light used is 6000Å . The path difference between PA and QA is$ (1) $1.4 \times 10^{- 4} cm$ (2) $2.7 \times 10^{- 4} cm$ (3) $4.5 \times 10^{- 4} cm$ (4) $6.2 \times 10^{- 4} cm$