$A$ parallel beam of monochromatic light of wavelength $5000 \mathring{A}$ is incident normally on a single narrow slit of width $0.001 \text{ mm}$. The light is focused by a convex lens on a screen placed on its focal plane. The first minima will be formed for the angle of diffraction of . . . . . . (degree).

In a single-slit diffraction experiment,the first minimum for a wavelength $\lambda_1 = 660 \ nm$ coincides with the first maximum for a wavelength $\lambda_2$. Find the value of $\lambda_2$ in $nm$.

In an experiment,electrons are made to pass through a narrow slit of width $'d'$ comparable to their de-Broglie wavelength. They are detected on a screen at a distance $'D'$ from the slit (see figure). Which of the following graphs can be expected to represent the number of electrons $'N'$ detected as a function of the detector position $'y'$ ($y = 0$ corresponds to the middle of the slit)?

When a compact disc is illuminated by a source of white light,coloured 'lanes' are observed. This is due to

Light of wavelength $6000 \ \mathring{A}$ is incident on a slit. The width of the slit is $0.30 \ mm$. A screen is placed at a distance of $2 \ m$ from the slit. Find the width of the central maximum in $mm$.

In a single slit diffraction experiment, the first minimum for red light $(660 \ nm)$ coincides with the first secondary maximum of some other wavelength $\lambda$. The value of $\lambda$ is $..... \mathring{A}$.