In order to see diffraction,the thickness of the film must be of the order of:

In a single-slit diffraction experiment, the slit is illuminated by light of two wavelengths $\lambda_1$ and $\lambda_2$. It is observed that the $2^{nd}$ order diffraction minimum for $\lambda_1$ coincides with the $3^{rd}$ diffraction minimum for $\lambda_2$. Then:

In a diffraction experiment from a single slit,the angular width of the central maximum does $NOT$ depend upon:

Radio waves diffract around buildings,although light waves do not. The reason is that radio waves

In the diffraction pattern of a single slit,the width of the secondary maxima compared to the central maximum is:

$A$ parallel beam of monochromatic light falls normally on a single narrow slit. The angular width of the central maximum in the resulting diffraction pattern