Electric field in a plane electromagnetic wave is given by ${E}=50 \sin \left(500 {x}-10 \times 10^{10} {t}\right) \,{V} / {m}$ The velocity of electromagnetic wave in this medium is :

(Given ${C}=$ speed of light in vacuum)

If an electromagnetic wave propagating through vacuum is described by $E_y=E_0 \sin (k x-\omega t)$; $B_z=B_0 \sin (k x-\omega t)$, then

The electric field of a plane electromagnetic wave is given by $\overrightarrow{ E }= E _{0}(\hat{ x }+\hat{ y }) \sin ( kz -\omega t )$ Its magnetic field will be given by

What happens to the intensity of light from a bulb if the distance from the bulb is doubled? As a laser beam travels across the length of a room, its intensity essentially remains constant. What geometrical characteristic of $LASER$ beam is responsible for the constant intensity which is missing in the case of light from the bulb ? 

A light wave is incident normally on a glass slab of refractive index $1.5$. If $4\%$ of light gets reflected and the amplitude of the electric field of the incident light is $30\, V/m$, then the amplitude of the electric field for the wave propagating in the glass medium will be.......$ V/m$

The intensity of light from a source is $\left( {\frac{{500}}{\pi }} \right)W/{m^2}$ . Find the amplitude of electric field in this wave