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

When a compact disc $(CD)$ is illuminated by a small source of white light,coloured bands are observed. This is due to

Assertion : Standard optical diffraction gratings cannot be used for discriminating between $X-$ray wavelengths.
Reason : The grating spacing is not of the order of $X-$ray wavelengths.

In a diffraction pattern, light of wavelength $580 \,nm$ is incident normally on a slit of width '$a$'. The distance between the slit and the screen is $2.5 \,m$ and the distance of the second-order maximum from the center of the screen is $14.5 \,mm$. The value of '$a$' is:

For a light of wavelength $5000 \, \mathring{A}$ incident normally on a slit,the first diffraction minimum is formed at an angle of $\theta = 30^\circ$. The width of the slit is:

Which of the following are true for a single slit diffraction?
$(A)$ Width of central maxima increases with increase in wavelength keeping slit width constant.
$(B)$ Width of central maxima increases with decrease in wavelength keeping slit width constant.
$(C)$ Width of central maxima increases with decrease in slit width at constant wavelength.
$(D)$ Width of central maxima increases with increase in slit width at constant wavelength.
$(E)$ Brightness of central maxima increases for decrease in wavelength at constant slit width.