Question

Maxwell in his famous equations of electromagnetism, introduced the concept of:

A: AC current
B: displacement current
C: Impedance
D: Reactance

Answer 1

Maxwell equations help us to illustrate the characteristics of light. He helped in describing the entire electromagnetic phenomena and he came to the conclusion that electromagnetic waves and visible light are similar. The equations lead to the explanation of the generation of electric and magnetic fields.

Complete step by step answer:
The Maxwell equations are partial differential equations that link the temporal and spatial change of both electric and magnetic fields. These spatial rates of changes are represented as divs and curls: or rather divergences and curls of the fields.
The following are the Maxwell equations of electromagnetism:
$\begin{aligned} & 1.\nabla .E=\dfrac{\rho }{\varepsilon } \\\ & 2.\nabla .B=0 \\\ & 3.\nabla \times E=\dfrac{-dB}{dt} \\\ & 4.\nabla \times B={{\mu }_{0}}J+\dfrac{1}{{{c}^{2}}}\dfrac{dE}{dt} \\\ \end{aligned}$
When we consider the fourth equation in this list of equations,
$\nabla \times B={{\mu }_{0}}J$, This is termed as the Ampere’s circuital law which is applicable only for steady currents. However Maxwell found this particular disadvantage and he modified the Ampere’s law in a way that it can incorporate the time varying electric and magnetic field in electromagnetic waves as well.
Hence, Maxwell introduced a new quantity called displacement current which is defined as the rate of change of electrical displacement field.
The value of displacement current can be calculated by the formula $\dfrac{1}{{{c}^{2}}}\dfrac{dE}{dt}$
Hence, this equation is further known as the Ampere-Maxwell law.
We can conclude that option B is the right answer among the four options.

Note: Maxwell explained the concept of displacement current using the case of a capacitor. That is when a capacitor starts charging, there is no charge conduction between the fields. However, due to charge accumulation in the plates with time, electric field changes causing the displacement current.