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JEE Main202127 Jul 2021Morning ShiftPhysicsMathematics in PhysicsActual

Assertion A : If A , B , C , D are four points on a semi-circular arc with a centre at O such that | A B → | = | B C → | = | C D → | . Then, A B → + A C → + A D → = 4 A O → + O B → + O C → Reason R : Polygon law of vector addition yields A B → + B C → + C D → + A D → = 2 A O → In the light of the above statements, choose the most appr

Options

  1. AA is correct but R is not correct.
  2. BA is not correct but R is correct.
  3. CBoth A and R are correct and R is the correct explanation of A .
  4. DBoth A and R are correct but R is not the correct explanation of A .

Correct answer

D. Both A and R are correct but R is not the correct explanation of A .

Step-by-step solution

Polygon law is applicable in both but the equation given in the reason is not useful in explaining the assertion.

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