Anukruti posted an Question
November 28, 2020 • 04:51 am 30 points
  • IIT JAM
  • Geology (GG)

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    Sajan sarthak best-answer

    We know optic axis is such an axis where no double refraction occurs so light passing through it parallely will definitely be stopped at analyser because both polariser and analyser has perpendicular vibration direction. so A section must cut perpendicular to optic axis for light passing parallel to optic axis. Option D IS THE ANSWER

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    Rahul kumar Best Answer

    Answer: Perpendicular to optic axis Any mineral behaves isotropic (complete extinction) when it is seen along the optic axis. For complete extinction throughout the 360° rotation of the stage, the section should be kept perpendicular to the optic axis of the mineral grain (for eg. a hexagonal mineral will remain extinct when the section perpendicular to the c axis (optic axis) is seen under microscope.

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