Ray Optics · JEE Main previous year questions

2010 3 questions

1. Q462010 · 25 Apr 2010 · Shift 1

   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 $I$ 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

   1. A.diverge
   2. B.converge
   3. C.diverge near the axis and converge near the periphery
   4. D.travel as a cylindrical beam
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   Answer: B

2. Q472010 · 25 Apr 2010 · Shift 1

   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 $I$ is the intensity of the light beam. The intensity of the beam is decreasing with increasing radius. The initial shape of the wavefront of the beam is

   1. A.convex
   2. B.concave
   3. C.convex near the axis and concave near the periphery
   4. D.planar
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   Answer: D

3. Q482010 · 25 Apr 2010 · Shift 1

   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 $I$ is the intensity of the light beam. The intensity of the beam is decreasing with increasing radius. The speed of light in the medium is

   1. A.minimum on the axis of the beam
   2. B.the same everywhere in the beam
   3. C.directly proportional to the intensity $I$
   4. D.maximum on the axis of the beam
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   Answer: A