In YDSE, refer to figure, d >> $\lambda$ and $\mathrm{\theta } = 30°$. The central bright fringe is obtained at distance x above Point C, then x is:

                      

1.  $\frac{\mathrm{D}}{2}$

2.  $\frac{D}{\sqrt{3}}$

3.  2D

4.  Zero

A parallel beam of white light falls on the plane of slits separated by a distance d. The distance above O, at which there will be bright fringe will be:

1.  $\frac{\mathrm{d}}{2}$

2.  $\frac{\mathrm{d}}{3}$

3.  $\frac{\mathrm{d}}{4}$

4.  $\frac{2\mathrm{d}}{3}$

White light is used for double-slit interference, for how many wavelengths, we get maximum at point P shown here on the screen?
                    

1.  1

2.  2

3.  3

4.  7

The figure here shows \(P\) and \(Q\) as two equally intense coherent sources emitting radiations of wavelength \(20~\text{m}\). The separation \(PQ\) is \(5.0~\text{m}\) and the phase of \(P\) is ahead of the phase of \(Q\) by \(90^{\circ}.\)$$\(A, B,\) and \(C\) are three distant points of observation equidistant from the midpoint of \(PQ\). The intensity of radiations at \(A,B,C\) will bear the ratio:

               
1. \(0:1:4\)
2. \(4:1:0\)
3. \(0:1:2\)
4. \(2:1:0\)

In Young's double-slit experiment the intensity of light on screen due to each slit is ${\mathrm{I}}_0$ Interference pattern is observed along a direction parallel to the line $S_1{S}_2$, on-screen S

The minimum, maximum, and the intensity averaged over the entire screen are respectively:

1.  0, 4${\mathrm{l}}_0$, 2${\mathrm{l}}_0$

2.  0, 4${\mathrm{l}}_0$, ${\mathrm{l}}_0$

3.  ${\mathrm{l}}_0$, 2${\mathrm{l}}_0$, 3${\mathrm{l}}_0$/2

4.  0, $2{\mathrm{I}}_0$, ${\mathrm{l}}_0$

An unpolarized beam of light of intensity passes through two linear polarizers making an
angle of 30$°$ with respect to each other. The emergent beam will have an intensity:

1.  $\frac{3{\mathrm{l}}_0}{4}$

2.  $\frac{\sqrt{3}{\mathrm{l}}_0}{4}$

3.  $\frac{3{\mathrm{l}}_0}{8}$

4.  $\frac{{\mathrm{l}}_0}{8}$

A beam of monoenergetic electrons, which have been accelerated from rest by a potential U, is used to form an interference pattern in Young's double-slit experiment. The electrons are now accelerated by potential 4U. The fringe width:

1.  Remains the same

2.  Is half the original fringe width

3.  Is twice the original fringe width

4.  Is one-fourth the original fringe width

A source of light $\left(f = 6.0 \times {10}^{14} Hz \right)$ passes through three planes polarizes. The first two polarizers are in the same direction, while the third is rotated $90°$ with respect to the second polarizer. What is the frequency of the light that comes out of the third polarizer?

1.  $3.0 \times {10}^{14} Hz$

2.  $6.0 \times {10}^{14} Hz$

3.  $9.0 \times {10}^{14} Hz$

4.  Light will not pass through the third polarizer

In young's experiment, the wavelength of red light is $7.8\times {10}^{-5}$ cm and that of blue light $5.2\times {10}^{-5}$ cm. The value of n for which (n+1)th blue bright band coincides with the nth red band is:

1. 4

2. 3

3. 2

4. 1

Light of wavelength 6000 $\stackrel{0}{A}$ is incident on a single slit. The first minimum of the diffraction pattern is obtained at 4 mm from the center. The screen is at a distance of 2 m from the slit. The slit width will be:

1. 0.3 mm

2. 0.2 mm

3. 0.15 mm

4. 0.1 mm