Who discovered for the first time that a changing electric field can produce a magnetic field?

"Changing electric field produces magnetic field". Explain the importance of the given statement.

$A$ parallel plate capacitor with circular plates of radius $1\, m$ has a capacitance of $1 \;nF$. At $t=0,$ it is connected for charging in series with a resistor $R=1 \;M \Omega$ across a $2 \;V$ battery (Figure). Calculate the magnetic field at a point $P$,halfway between the centre and the periphery of the plates,after $t=10^{-3}\; s$.
(The charge on the capacitor at time $t$ is $q(t)=C V[1-\exp (-t / \tau)],$ where the time constant $\tau$ is equal to $C R .$ )

According to Maxwell,which is the missing term in Maxwell-Ampere circuital law?

Which scientist experimentally proved the existence of electromagnetic waves?

What is the effect of displacement current?