, , and and Hyperbolic bright and dark bands with foci symmetrically placed about O in the x-direction

, will result in -2 marks, as a wrong option is also darkened. While conducting the Young's double slit experiment, a student replaced the two slits with a large opaque plate in the x-y plane containing two small holes that act as two coherent point sources (S 1 , S 2 ) emitting light of wavelength 600 nm. The student mistakenly placed the screen parallel to the x-z plane (for z > 0) at a distance D = 3 m from the mid-point of S 1 S 2 , as shown schematically in the figure. The distance between the sources d = 0.6003 mm. The origin O is at the intersection of the screen and the line joining S 1 S 2 . which of the following is(are) true of the intensity pattern on the screen? Semi circular bright and dark bands centred at point O

and and The region very close to the point O will be dark

. ONE OR MORE THAN ONE of these four option(s) is(are) correct. • For each question, marks will be awarded in one of the following categories: Full Marks : +4 If only the bubble(s) corresponding to all the correct option(s) is(are) darkened. Partial Marks : +1 For darkening a bubble corresponding to each correct option, provided NO incorrect option is darkened. Zero Marks : 0 If none of the bubbles is darkened. Negative Marks : -2 In all other cases. • For example, if are all the correct options for a question, darkening all these three will result in +4 marks; darkening only will result in +2 marks; and darkening Straight bright and dark bands parallel to the x-axis