Question

            (a.) Light of wavelength 5.5 × 10^-7m falls on a single silt of width 0.15mm. A screen is placed 1.2m beyond the slit.

             (i.) Name the phenomenon that occurs.

              (ii) Sketch a graph showing the light pattern observed on the screen.

             (iii.) Calculate the width of the central fringe.

Answer 1

(I). The phenomenon is diffraction.

(II).

(III).

$Width\:of\:central\:fringe\left(Y_m\right)$

$=\frac{Order\:of\:maximum\left(m\right)\times Wavelength\left(\lambda \right)\times distance\:from\:slit\left(L\right)}{Width\:of\:the\:slit\left(D\right)}$

$=\frac{m\lambda L}{D}$

$=\frac{\left(1x5.5x10^{-7}x1.2\right)}{\left(0.15x10^{-3}\right)}$

$=4.4x10^{-3}m$