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

An accelerated electron produces ...

$A$ parallel plate capacitor (Figure) made of circular plates each of radius $R=6.0\; cm$ has a capacitance $C=100\; pF$. The capacitor is connected to a $230\; V$ ac supply with a (angular) frequency of $300 \;rad \;s ^{-1}$.
$(a)$ What is the rms value of the conduction current?
$(b)$ Is the conduction current equal to the displacement current?
$(c)$ Determine the amplitude of $B$ at a point $3.0\; cm$ from the axis between the plates.

If $\varepsilon_0$ denotes the permittivity of free space and $\phi_{E}$ is the flux of the electric field through the area bounded by the closed surface,then the dimensions of $\left(\varepsilon_0 \frac{d \phi_{E}}{dt}\right)$ are that of

Which is the missing term in Ampere's circuital law?

$A$ variable frequency $AC$ source is connected to a capacitor. How will the displacement current change with a decrease in frequency?