Let $S_1 and S_2$ be the two slits in Young's double-slit experiment. If central maxima is observed at P and angle $\angle S_{1}P{S}_2=\theta$, then the fringe width for the light of wavelength $\lambda$ will be (assume $\theta$ to be a small angle)

1. $\lambda$/$\theta$

2. $\lambda$$\theta$

3. 2$\lambda$/$\theta$

4. $\lambda$/2$\theta$

In YDSE, coherent monochromatic light having wavelength 600 nm falls on the slits. The first-order bright fringe is at 4.84 mm from central maxima. Determine the wavelength for which the first-order dark fringe will be observed at the same location on the screen. (Take D=3 m)

1. 600 nm

2. 1200 nm

3. 300 nm

4. 900 nm

$\mathrm{Unpolarized} \mathrm{light} \mathrm{of} \mathrm{intensity} 32 {\mathrm{Wm}}^{-2} \mathrm{passes} \mathrm{through} \mathrm{three} \mathrm{polarizers} \mathrm{such} \mathrm{that}$
$\mathrm{transmission} \mathrm{axes} \mathrm{of} \mathrm{the} \mathrm{first} \mathrm{and} \mathrm{second} \mathrm{polarizer} \mathrm{makes} \mathrm{an} \mathrm{angle} {30}^0 \mathrm{with} \mathrm{each}$
$\mathrm{other} \mathrm{and} \mathrm{transmission} \mathrm{axis} \mathrm{of} \mathrm{the} \mathrm{last} \mathrm{polarizer} \mathrm{is} \mathrm{crossed} \mathrm{with} \mathrm{that} \mathrm{of} \mathrm{the} \mathrm{first}.\mathrm{The}$
$\mathrm{intensity} \mathrm{the} \mathrm{final} \mathrm{emerging} \mathrm{light} \mathrm{will} \mathrm{be}:$

1. 32 $W{m}^{-2}$

2. 3 $W{m}^{-2}$

3. 8 $W{m}^{-2}$

4. 4 $W{m}^{-2}$

When unpolarized light beam is incident from air onto glass (n=1.5) at the polarizing angle:

1. Reflected beam is polarized 100 percent

2. Reflected and refracted beams are partially polarized

3. The reason for (1) is that almost all the light is reflected 

4. All of the above

When the angle of incidence on a material is $60°$, the reflected light is completely polarized. The velocity of the refracted ray inside the material is (in $m{s}^{-1}$)

1. $3\times {10}^8$

2. $\left(\frac{3}{\sqrt{2}}\right)\times {10}^8$

3. $\sqrt{3}\times {10}^8$

4. $0.5\times {10}^8$

A polaroid is placed at $45°$ to an incoming light of intensity $I_0$. Now the intensity of light passing through polaroid after polarization would be?

1.  $I_0$

2.  $I_0$/2

3.  I/4

4.  Zero

Yellow light is used in a single slit diffraction experiment with slit width 0.6 mm. If the yellow light is replaced by X-rays then the pattern will reveal:

1.  that the central maxima is narrower

2.  no diffraction pattern

3.  more number of fringes

4.  less number of fringes

What will be the angular width of the central maximum in Fraunhofer diffraction when the light of wavelength 6000 $\stackrel{0}{A}$ is used and slit width is $12 \times {10}^{-5}$ cm?

1.  2 rad

2.  3 rad

3.  1 rad

4.  8 rad

If we observe the single slit Fraunhofer diffraction with a wavelength $\lambda$ and slit width d, the width of the central maximum is 2$\theta$. On decreasing the slit width for the same $\lambda$

1.  $\theta$ increases

2.  $\theta$ remains unchanged

3.  $\theta$ decreases

4.  $\theta$ increases or decreases depending on the intensity of light

A slit of width a is illuminated by white light. For red light $\left(\mathrm{\lambda } = 6500 \stackrel{0}{A}\right)$, the first minima is obtained at $\theta$ = $30°$. Then the value of a will be:

1.  3250 $\stackrel{0}{A}$

2.  $6.5 \times {10}^{-14}$ mm

3.  1.24 microns

4.  $2.6 \times {10}^{-4}$ cm