Which of the following are true for a single slit diffraction?
A. Width of central maxima increases

Question

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.

Professor PC Thomas Classes · Answer

In a single slit diffraction pattern, the width of the central maximum is given by $W = \frac{2\lambda D}{a}$, where $\lambda$ is the wavelength and $a$ is the slit width. Thus, the width $W$ is directly proportional to the wavelength $\lambda$ (Statement A is true) and inversely proportional to the slit width $a$ (Statement C is true).