In an interference experiment,the ratio of amplitudes of coherent waves is $\frac{a_1}{a_2} = \frac{1}{3}$. The ratio of maximum and minimum intensities of fringes will be

Interference fringes are produced on the screen by using two light sources of intensities $I$ and $9I$. The phase difference between the beams is $\pi / 2$ at point $P$ and $\pi$ at point $Q$ on the screen. The difference between the resultant intensities at points $P$ and $Q$ is $(\cos 90^{\circ}=0, \cos 180^{\circ}=-1)$. (in $I$)

To produce the phenomenon of interference,we require two sources that emit radiation of:

Two coherent sources of intensities,$I_1$ and $I_2$ produce an interference pattern. The maximum intensity in the interference pattern will be

Two light rays having the same wavelength $\lambda$ in vacuum are in phase initially. Then the first ray travels a path $L_1$ through a medium of refractive index $\mu_1$,while the second ray travels a path of length $L_2$ through a medium of refractive index $\mu_2$. The two waves are then combined to observe interference. The phase difference between the two waves is

The intensities of two coherent light waves are $I$ and $4I$. The maximum intensity of the resultant wave after interference is: (in $I$)