In the interference experiment using a biprism, the distance of the slits from the screen is increased by $$25 \%$$ and the separation between the slits is halved. If '$$W$$' represents the original fringewidth, the new fringewidth is

In biprims experiment, the $$4^{\text {th }}$$ dark band is formed opposite to one of the slits. The wavelength of light used is $$(\mathrm{d}=$$ distance between the slits, $$\mathrm{D}=$$ distance between scource and the screen)

In Young's double slit experiment using monochromatic light of wavelength '$$\lambda$$', the maximum intensity of light at a point on the screen is $$\mathrm{K}$$ units. The intensity of light at point where the path difference is $$\frac{\lambda}{3}$$ is

$$\left[\cos 60^{\circ}=\sin 30^{\circ}=\frac{1}{2}\right]$$

If two sources emit light waves of different amplitudes then