Two periodic waves of intensities I₁ and I₂ pass through a region at the same time in the same direction. The sum of the maximum and minimum intensities is :-

1. I₁ + I₂

2. ${\left(\sqrt{{\mathrm{I}}_1}+\sqrt{{\mathrm{I}}_2}\right)}^2$

3. ${\left(\sqrt{{\mathrm{I}}_1}-\sqrt{{\mathrm{I}}_2}\right)}^2$

4. 2(I₁ + I₂)

In a double slit experiment, instead of taking slits of equal widths, one slit is made twice as wide as the other. Then, in the interference pattern :-

1. the intensities of both the maxima and the minima increase

2. the intensity of the maxima increases and the minima has zero intensity

3. the intensity of the maxima decreases and that of the minima increases

4. the intensity of the maxima decreases and the minima has zero intensity

In refraction. light waves are bent on passing from one medium to the second medium, because in the second medium :

1. the frequency is different

2. the coefficient of elasticity is different

3. the speed is different

4. the amplitude is smaller

To demonstrate the phenomenon of interference we require two sources which emit radiations of :

1. nearly the same frequency

2. the same frequency

3. different wavelength

4. the same frequency and having a definite phase relationship

In a mica sheet of thickness t and refractive index $\mathrm{\mu }$ is placed in the path of one of interfering beam in a double slit experiment, then displacement of fringes will be :-

1. $\frac{\mathrm{D}}{\mathrm{d}}\mathrm{\mu t}$

2. $\frac{\mathrm{D}}{\mathrm{d}}(\mathrm{\mu }-1)\mathrm{t}$

3. $\frac{\mathrm{D}}{\mathrm{d}}(\mathrm{\mu }+1)\mathrm{t}$

4. $\frac{\mathrm{D}}{\mathrm{d}}\left({\mathrm{\mu }}^2-1\right)\mathrm{t}$

In Young's double slit experiment maximum intensity is I than the angular position where the intensity becomes $\frac{1}{4}$ is :

1. ${\sin }^{-1}\left(\frac{\lambda }{d}\right)$

2. ${\sin }^{-1}\left(\frac{\lambda }{3d}\right)$

3. ${\sin }^{-1}\left(\frac{\lambda }{2d}\right)$

4. ${\sin }^{-1}\left(\frac{\lambda }{4d}\right)$

Fringe width due to interference of two coherent sources is $\mathrm{\beta }$. If frequency of sources is tripled, new fringe width will be :-

1. 3$\mathrm{\beta }$

2. $\mathrm{\beta }$ / 3

3. 2$\mathrm{\beta }$

4. $\mathrm{\beta }$ / 2

Two coherent sources of wavelength $\mathrm{\lambda }=6.2\times {10}^{-7} \mathrm{m}$ produce interference. Path difference corresponding to 10^th bright band will be :-

1. 6.2 x 10^-6 m

2. 3.1 x 10^-6 m

3. 1.5 x 10^-6 m

4. 12.4 x 10^-6 m

A window with grills is seen through a telescope at a distance of 200 m. Distance between grill wires is 2 mm. Wavelength of light used is 5000A. Minimun diameter of telescope should be :-

1. 6.1 cm

2. 5.9 cm

3. 2 cm

4. 3.6 cm

Diffraction pattern can be seen :-

1. Only in sound waves

2. Only in light waves

3. Only in ultrasonic waves

4. in sound and light waves