$A$ circular parallel plate capacitor of radius $R$ and spacing $d$ is being charged by a constant current $I_D$. Find the magnetic field between the plates at a distance $r$ from the axis,where $r > R$.

What was the primary difficulty in establishing the wave theory of light,and who explained it?

Which scientist experimentally proved the existence of electromagnetic waves?

$A$ parallel plate capacitor is completely immersed in a liquid of resistivity $\rho = 0.25 \, \Omega m$ and relative permittivity $\epsilon_r = 80$. If the plates of the capacitor are connected to an alternating voltage source of $V = V_0 \sin(\omega t)$ at a frequency of $f = 0.4 \, GHz$,then the ratio of the amplitudes of the displacement current $(I_d)$ and conduction current $(I_c)$ is:

What did Hertz observe in his experiment to produce electromagnetic waves?

What suggestion was made to correct the discrepancies in Ampere's circuital law?