Production of em waves Drawing of sketch of linearly polarized em waves Indication of directions of oscillating electric and magnetic fields A charge oscillating with some frequency, produces an oscillating electric field in space, which in turn produces an oscillating magnetic field perpendicular to the electric field, this process goes on repeating, producing em waves in space perpendicular to both the fields. Directions of $\overset{\rightarrow}{E}$ and $\overset{\rightarrow}{B}$ are perpendicular to each other and also perpendicular to direction of propagation of em waves. ORMaxwell's generalization of Ampere's Circuital lawShowing that current produced, within the plates of a capacitor is $i=\varepsilon_0 \;\frac{d\phi_E}{dt}$ Ampere's circuital law is given by as $\phi \overset{\rightarrow}{B} \cdot \overset{\rightarrow}{d l} = \mu_{o} i_c$ But for a circuit containing capacitor, during its charging / discharging the current within the plates of the capacitor varies, (producing displacement current $i_d$ ). Therefore, the above equation, as generalized by Maxwell, is given as $\phi \overset{\rightarrow}{B} \cdot \overset{\rightarrow}{d l} = \mu_0 i_c + \mu_0 i_d$During the process of charging of capacitor, electric flux $(\varphi_E)$ between the plates of capacitor changes with time, which produces the current within the plates of capacitor. This current, being proportional to $\;\frac{d\phi_E}{dt}$ , we have $i=\varepsilon_o \;\frac{d\phi_E}{dt}$