In an electromagnetic wave, the ratio of electric field intensity (E) to magnetic field intensity (H) in a medium is given by:
$\frac{E}{H} = \sqrt{\frac{\mu}{\epsilon}} = \sqrt{\frac{\mu_r \mu_0}{\epsilon_r \epsilon_0}} = \sqrt{\frac{\mu_0}{\epsilon_0}} \sqrt{\frac{\mu_r}{\epsilon_r}}$
Given that $\sqrt{\frac{\mu_0}{\epsilon_0}} = 120\pi$ and $\frac{\mu_r}{\epsilon_r} = \frac{1}{4}$:
$\frac{E}{H} = 120\pi \sqrt{\frac{1}{4}} = 60\pi$
Thus, the ratio of E to H is 60π : 1.
The following diagram shown restriction sites in E. coli cloning vector pBR322. Find the role of ‘X’ and ‘Y’gens :