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NEET2026PhysicsChapterActual

An electromagnetic wave travels through a medium having relative permittivity _r and relative permeability _r . If a new medium is chosen such that its relative permittivity is 2 _r and relative permeability is _r 2 , the speed of the electromagnetic wave in the new medium compared to the original medium will:

Options

  1. Aremain the same
  2. Bbe doubled
  3. Cbe halved
  4. Dincrease by a factor of 2

Correct answer

A. remain the same

Step-by-step solution

The speed of an electromagnetic wave in a medium is given by v = 1 = c _r _r . For the original medium, v₁ = c _r _r . For the new medium, the relative permittivity is 2 _r and the relative permeability is _r 2 . The speed in the new medium is v₂ = c ( _r 2 ) (2 _r) = c _r _r . Thus, v₂ = v₁ . The speed of the electromagnetic wave remains the same. Answer: remain the same

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