Q86 / 90 · JEE Main 2010 · Physics
An initially parallel cylindrical beam travels in a medium of refractive index $\mu(I)=\mu_0+\mu_2 I$, where $\mu_0$ and $\mu_2$ are positive constants and $\mathrm{I}$ is the intensity of the light beam. The intensity of the beam is decreasing with increasing radius.
As the beam enters the medium, it will
- Adiverge
- Correct answerBconverge
- Cdiverge near the axis and converge near the periphery
- Dtravel as a cylindrical beam
Solution
As intensity is maximum at axis,
$\therefore \quad \mu$ will be maximum and speed will be minimum on the axis of the beam.
$\therefore \quad$ beam will converge.
Hence, the correct answer is option: 'B'.