By a monochromatic wave,we mean

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

If the amplitude ratio of two sources producing interference is $3:5$,the ratio of intensities at maxima and minima is

Consider the following statements about interference of light.
$A$-When crest of one wave coincides with crest of another wave at a point,this point is a point of destructive interference.
$B$-Two coherent sources emit waves of the same frequency with a constant phase difference.
Choose the correct option from the following.

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

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