The electric and magnetic fields associated with an electromagnetic wave propagating along the $Z$-axis can be represented by:

For a plane electromagnetic wave,the magnetic field at a point $x$ and time $t$ is $\overrightarrow{ B }( x , t ) = [1.2 \times 10^{-7} \sin (0.5 \times 10^{3} x + 1.5 \times 10^{11} t) \hat{ k }] \text{ T}$. The instantaneous electric field $\overrightarrow{ E }$ corresponding to $\overrightarrow{ B }$ is: (speed of light $c = 3 \times 10^{8} \text{ m/s}$)

If $\vec{E}$ and $\vec{B}$ are the electric and magnetic field vectors of an electromagnetic wave,then the direction of propagation of the electromagnetic wave is

If the direction of propagation of an electromagnetic wave is along the $z$-axis,then the directions of the electric field $(E)$ and magnetic field $(B)$ are:

The ratio of the speeds of electromagnetic waves in a vacuum and in a medium with dielectric constant $K=3$ and permeability $\mu=2\mu_{0}$ is (where $\mu_{0}$ is the permeability of vacuum).

Which of the following quantities changes when the velocity of light in a vacuum changes?