Diffraction and interference of light suggest

The ratio of the amplitudes of two interfering waves is $3 : 4$. What is the ratio of their intensities?

When two light waves of equal intensity superimpose, the maximum intensity obtained is $I$. If the intensity of one of the waves is quadrupled, then the maximum intensity obtained is

The path difference between two interfering waves at a point on the screen is $171.5$ times the wavelength. If the path difference is $0.01029 \, cm$,find the wavelength in $\mathring{A}$.

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?

The path difference between two interference waves at a point on a screen is $11.5 \lambda$. The point is