The number of fringes in the field of view of YDSE is 30 in air. If the experiment is performed in water $\left(\mu =\frac{4}{3}\right)$, then the number of fringes in the field of view will be 

1. 30

2. 50

3. 40

4. 60 

Which of the following property of light is a sure proof of wave nature of light?

1.  Interference 

2.  Diffraction

3.  Photoelectric Effect

4.  Both (1) & (2)

In Young's double slit experiment, a slit is covered with a thin film so that the optical path difference introduced between coherent waves is $5\lambda$. Then the new position of central maxima will be at

1.  The initial position of 5th maxima

2.  The initial position of 3rd minima

3.  The initial position of 2nd minima

4.  The initial position of 3rd maxima

In Young's double-slit experiment using the light of wavelength '$\lambda$', 60 fringes are seen on a screen. If the wavelength of light is decreased by 50%, then the number of fringes on the same screen will be:

1.  30

2.  60

3.  120

4.  90

If the polarising angle for a material is $60°$, then the refractive index of the material will be:

1.  $\frac{1}{\sqrt{3}}$

2.  $\frac{3}{2}$

3.  $\sqrt{3}$

4.  $\frac{\sqrt{3}}{2}$

The geometrical path of a ray of light in a medium of refractive index 2 is 8 m. The optical  path is

1.  16 m

2.  4 m

3.  2 m

4.  1 m

In Young's double-slit experiment if the separation of the screen is increases from slits, the fringe width will 

1.  Decrease

2.  Increase

3.  Remain the same

4.  Any of the above depending on the wavelength of the light used

Five identical polaroids are placed coaxially with \(45^{\circ}\) angular separation between pass axes of adjacent polaroids as shown in the figure. (I₀: Intensity of unpolarized light)
          
The intensity of light, I, emerging out of the 5^th polaroid is:

1.  $\frac{{\mathrm{I}}_0}{4}$

2.  $\frac{{\mathrm{I}}_0}{8}$

3.  $\frac{{\mathrm{I}}_0}{16}$

4.  $\frac{{\mathrm{I}}_0}{32}$

In Young's double-slit experiment, how many minimas can be obtained on a screen, if the wavelength of light used is 2000 $\stackrel{\mathrm{o}}{\mathrm{A}}$ and slit width is 0.0008 mm?

1.  6

2.  7

3.  8

4.  9

When YDSE is carrying out in liquid, 5th bright fringe lies at a point on the screen where 3rd dark fringe was lying in the air. The refractive index of the medium is

1.  1.5

2.  3

3.  2

4.  1.2