What happens if we close one slit in a Young's double-slit experiment?

Visible light of wavelength $6000 \times 10^{-8} \; cm$ falls normally on a single slit and produces a diffraction pattern. It is found that the second diffraction minimum is at $60^{\circ}$ from the central maximum. If the first minimum is produced at $\theta_{1}$,then $\theta_{1}$ is close to.....$^{\circ}$

In the case of Fraunhofer diffraction due to a single slit,the intensity of the central maximum is $I_0$. If the width of the slit is doubled,what will be the new intensity of the central maximum?

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

The phenomenon that explains why light waves do not travel in a straight line is known as .......

Light of wavelength $5000 \, \mathring{A}$ is incident on a single slit such that the angular position of the first minima is $30^\circ$. The width of the slit is: