Diffraction and interference of light demonstrate the ....... of light.

$PQ$ represents a wavefront and $AO$ and $BP$ are the corresponding two rays. Find the condition on $Q$ for constructive interference at $P$ between ray $BP$ and the reflected ray $OP$.

For constructive interference to take place between two monochromatic light waves of wavelength $\lambda$, the path difference should be

Two light waves of intensity $I$ and $4I$ superpose at point $A$ with zero phase difference and at point $B$ with a phase difference of $\frac{\pi}{2}$. Calculate the difference of resultant intensities at point $A$ and $B$. (in $I$)

If the wavelength of light is $4000 \, Å$, then the number of waves in a length of $1 \, mm$ will be:

If the ratio of maximum and minimum intensities is $36 : 1$ in an interference pattern,then the ratio of amplitudes of the interfering waves is