To heat the food containing water,the frequency of the microwaves used in a microwave oven is

An electromagnetic wave of frequency $1 \times 10^{14} \, Hz$ is propagating along the $z$-axis. The amplitude of the electric field is $4 \, V/m$. If $\varepsilon_0 = 8.8 \times 10^{-12} \, C^2/N \cdot m^2$,then the average energy density of the electric field will be:

In a plane electromagnetic wave,the average value of ....... is zero.

$A$ lamp emits monochromatic green light uniformly in all directions. The lamp is $3\%$ efficient in converting electrical power to electromagnetic waves and consumes $100\,W$ of power. The amplitude of the electric field associated with the electromagnetic radiation at a distance of $5\,m$ from the lamp will be nearly.......$V/m$

The electromagnetic waves travel in a medium at a speed of $2.0 \times 10^{8} \ m/s$. The relative permeability of the medium is $1.0$. The relative permittivity of the medium will be (in $.25$)

For an $EM$ wave,the electric field intensity due to a bulb of $100\ W$ at a distance of $3\ m$ is $E$. What is the electric field intensity produced by radiations coming from a $50\ W$ bulb at the same distance?