Question 11:
moderateWhich of the following conclusion can be drawn if an electromagnetic wave satisfies the Ampere’s law for vacuum?
For an EM wave in vacuum, \(c = \frac{E_0}{B_0}\) and \(c = \frac{1}{\sqrt{\mu_0 \varepsilon_0}}\). Substituting \(\frac{B_0}{E_0} = \frac{1}{c}\) into \(mu_0 \varepsilon_0 = \frac{B_0}{E_0 c}\) gives \(mu_0 \varepsilon_0 = \frac{1}{c^2}\), which is true.
Question 12:
easyA $100 \Omega$ resistance and a capacitor of $100 \Omega$ reactance are connected in series across a $220 V$ source. When the capacitor is 50% charged, the peak value of the displacement current is:
(2016 – II)
In a series RC circuit, the displacement current equals the conduction current. Impedance $Z = \sqrt{R^2 + X_C^2} = \sqrt{100^2 + 100^2} = 100\sqrt{2} \Omega$.
RMS current is $I_{rms} = \frac{V_{rms}}{Z} = \frac{220}{100\sqrt{2}} = \frac{2.2}{\sqrt{2}} A$.
Peak current is $I_0 = \sqrt{2} I_{rms} = \sqrt{2} \times \frac{2.2}{\sqrt{2}} = 2.2 A$.