To observe a stationary interference pattern formed by two light waves,it is not necessary that they must have :

Two coherent monochromatic point sources $S_1$ and $S_2$ of wavelength $\lambda = 600 \ nm$ are placed symmetrically on either side of the centre of the circle as shown. The sources are separated by a distance $d = 1.8 \ mm$. This arrangement produces interference fringes visible as alternate bright and dark spots on the circumference of the circle. The angular separation between two consecutive bright spots is $\Delta \theta$. Which of the following options is/are correct?
$[A]$ $A$ dark spot will be formed at the point $P_2$
$[B]$ At $P_2$ the order of the fringe will be maximum
$[C]$ The total number of fringes produced between $P_1$ and $P_2$ in the first quadrant is close to $3000$
$[D]$ The angular separation between two consecutive bright spots decreases as we move from $P_1$ to $P_2$ along the first quadrant

The displacements of two interfering light waves are given by $y_1 = 4 \sin \omega t$ and $y_2 = 3 \sin (\omega t + \frac{\pi}{2})$. What is the amplitude of the resultant wave?

Two coherent sources of wavelength $\lambda$ produce a steady interference pattern. The path difference corresponding to the $10^{\text{th}}$ order maximum will be:

Two monochromatic coherent light waves of amplitudes $A$ and $2A$,interfering at a point,have a phase difference of $60^{\circ}$. The intensity at that point will be proportional to (in $A^2$)

If two sources of light emit waves of different amplitudes and interfere, then: