In Young's double-slit experiment,the intensity of the central maximum is $I_0$. If one of the slits is closed,the intensity of the central maximum becomes .....

In Young's double-slit experiment,if the amplitudes of the interfering waves are not equal,then . . . . .

Two coherent sources $P$ and $Q$ produce interference at point $A$ on the screen,where a dark band is formed between the $4^{\text{th}}$ bright band and the $5^{\text{th}}$ bright band. The wavelength of the light used is $6000 \text{ Å}$. The path difference between $PA$ and $QA$ is:

In Young's double-slit experiment,if the separation between the slit and the screen increases,the fringe width:

If the source of light used in a Young's double slit experiment is changed from red to violet:

In Young's double slit experiment, the width of the second slit is double the width of the first slit. Consequently, the amplitude of the light from the two slits is different. If $I_m$ is the maximum intensity, the resultant intensity $I$ when they interfere with a phase difference of $\phi$ is given by: