Intensities of the two waves of light are $I$ and $4I$. The maximum intensity of the resultant wave after superposition is (in $I$)

When a light wave goes from air into water,the quality that remains unchanged is its

Two independent monochromatic light sources produce waves given by $y_1 = 2 \sin \omega t$ and $y_2 = 3 \cos \omega t$. Which of the following statements is true?

Two light beams having intensities $I$ and $9I$ interfere to produce a fringe pattern on a screen. The phase difference between the beams is $\frac{\pi}{2}$ at point $P$ and $\pi$ at point $Q$. The difference between the resultant intensities at $P$ and $Q$ will be ....... $I$.

Two identical radiators have a separation of $d = \lambda /4$ where $\lambda$ is the wavelength of the waves emitted by either source. The initial phase difference between the sources is $\pi /4$. Then the intensity on the screen at a distant point situated at an angle $\theta = 30^\circ$ from the radiators is (here $I_o$ is the intensity at that point due to one radiator alone):

If the distance between a point source and a screen is doubled,then the intensity of light on the screen will become: