Question

You need to use your cell phone, which broadcasts an $800\mathrm{MHz}$signal, but you're behind two massive, radio-wave absorbing buildings that have only a$15\mathrm{m}$space between them. What is the angular width, in degrees, of the electromagnetic wave after it emerges from between the buildings$?$

Short answer

Angular width of electromagnetic radiation is$2.86°$.

Step-by-step solution

Formula for angular width 

The width of the angular fringe is that the distance seen between centre fringe and therefore the slit. It also demonstrates how far the fringes are angularly.

Angular width is,

$\mathrm{\theta }=\frac{2\mathrm{\lambda }}{\mathrm{a}}$

$\mathrm{\lambda }$is wavelength.

$\mathrm{a}$is length of the slit.

Calculation of angular width

Angular width of electromagnetic wave:

$\mathrm{\theta }=\frac{2\mathrm{\lambda }}{\mathrm{a}}$

So,

$\mathrm{\theta }=\frac{2\mathrm{c}}{\mathrm{a\nu }}$

$=\frac{2\times 3\times {10}^8}{15\times 8\times {10}^8}$

$=0.05\mathrm{rad}$

$=2.86°$