Wave Optics · JEE Main previous year questions

2012 5 questions

1. Q542012 · 26 May 2012 · Shift 1

   In Young's double slit interference experiment, the slit widths are in the ratio $1:25$. Then the ratio of intensity at the maxima and minima in the interference pattern is

   1. A.$3:2$
   2. B.$1:25$
   3. C.$9:4$
   4. D.$1:5$
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   Answer: C

2. Q522012 · 12 May 2012 · Shift 1

   The first diffraction minimum due to the single slit diffraction is seen at $\theta =30^{\circ }$ for a light of wavelength $5000\mathring{\mathrm{A}}$ falling perpendicularly on the slit. The width of the slit is

   1. A.$2.5\times 10^{-5}\mathrm{cm}$
   2. B.$1.25\times 10^{-5}\mathrm{cm}$
   3. C.$10\times 10^{-5}\mathrm{cm}$
   4. D.$5\times 10^{-5}\mathrm{cm}$
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   Answer: C

3. Q532012 · 12 May 2012 · Shift 1

   The maximum number of possible interference maxima for slit separation equal to $1.8\lambda$, where $\lambda$ is the wavelength of light used, in a Young's double slit experiment is

   1. A.zero
   2. B.3
   3. C.infinite
   4. D.5
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   Answer: B

4. Q542012 · 7 May 2012 · Shift 1

   In a Young's double slit experiment with light of wavelength $\lambda$, fringe pattern on the screen has fringe width $\beta$. When two thin transparent glass (refractive index $\mu$) plates of thickness $t_1$ and $t_2$ ($t_1>t_2$) are placed in the path of the two beams respectively, the fringe pattern will shift by a distance

   1. A.$\frac{\beta (\mu -1)}{\lambda }\left(\frac{t_1}{t_2}\right)$
   2. B.$\frac{\mu \beta }{\lambda }\frac{t_1}{t_2}$
   3. C.$\frac{\beta (\mu -1)}{\lambda }(t_1-t_2)$
   4. D.$(\mu -1)\frac{\lambda }{\beta }(t_1+t_2)$
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   Answer: C

5. Q552012 · 7 May 2012 · Shift 1

   Two polaroids have their polarizing directions parallel so that the intensity of a transmitted light is maximum. The angle through which either polaroid must be turned if the intensity is to drop by one-half is

   1. A.$135^{\circ }$
   2. B.$90^{\circ }$
   3. C.$120^{\circ }$
   4. D.$180^{\circ }$
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   Answer: A