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NEET2026PhysicsChapterActual

A monochromatic light beam travels through two different transparent media, A and B. It is observed that a distance y in medium A contains n_A waves of this light, while a distance 3y in medium B contains n_B waves. If medium A is optically denser than medium B, what is the critical angle for total internal reflection at the interface of the two media?

Options

  1. A⁻¹ ( n_B 3n_A )
  2. B⁻¹ ( 3n_A n_B )
  3. C⁻¹ ( n_A 3n_B )
  4. D⁻¹ ( 3n_B n_A )

Correct answer

A. ⁻¹ ( n_B 3n_A )

Step-by-step solution

Let _A and _B be the wavelengths of light in medium A and medium B respectively. The number of waves in a given distance is the distance divided by the wavelength. For medium A: n_A = y _A _A = y n_A For medium B: n_B = 3y _B _B = 3y n_B The refractive index of a medium is inversely proportional to the wavelength of light in it. Thus, the relative refractive index of medium B with respect to medium A is: _B _A = _A _B Substituting the values of _A and _B : _B _A = y n_A 3y n_B = n_B 3n_A The critical angle _c for t

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