MCQ
Fraunhofer diffraction pattern of a parallel beam of light (wavelength $\lambda$ ) passing through a narrow slit (width $a$ ) is observed on a screen using a convex lens (focal length $f$ ). The angular half-width of the central fringe is
- A$\frac{2 \lambda f}{a}$
- B$\frac{\lambda f}{a}$
- C$\frac{2 \lambda}{a}$
- ✓$\frac{\lambda}{a}$
