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Concepts Of Physics MCQ Edition [Volume 2]PhysicsThe Special Theory of Relativity

A rod having a rest length L travels at a relativistic speed. Let L' = L/ . Its length

Options

  1. Amay be equal to L
  2. Bmay be more than L' but less than L
  3. Cmust be equal to L'
  4. Dmay be more than L

Correct answer

B. may be more than L' but less than L

Step-by-step solution

The length of a moving rod depends on its orientation with respect to the direction of motion. Let the rod be oriented at an angle with the direction of motion in its rest frame. The component of the length parallel to the velocity is L_ = L . The component of the length perpendicular to the velocity is L_ = L . Due to length contraction, the parallel component in the moving frame becomes L'_ = L . The perpendicular component remains unchanged, so L'_ = L . The total length of the rod in the moving frame is L_ movi

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