Two coherent sources of light can be obtained by

Resultant intensity at the centre of the screen due to two coherent sources is $I_0$. If the sources are incoherent,then the intensity at the same point will be

Write the condition for constructive interference in terms of path and phase difference.

Two waves of same intensity $I_0$ emitted from two sources having same phase difference $(\phi)$. Due to superposition of two waves,the intensity of resultant wave is directly proportional to . . . . . . .

The figure shows two point sources which emit light of wavelength $\lambda$ in phase with each other and are at a distance $d = 5.5 \lambda$ apart along a line which is perpendicular to a large screen at a distance $L$ from the center of the sources. Assume that $d$ is much less than $L$. Which of the following statement$(s)$ is (are) correct?

Four light sources produce the following four waves:
$(i)$ $y_1 = a \sin(\omega t + \phi_1)$
(ii) $y_2 = a \sin(2\omega t)$
(iii) $y_3 = d' \sin(\omega t + \phi_2)$
(iv) $y_4 = d' \sin(3\omega t + \phi)$
Superposition of which two waves gives rise to interference?