If radiation is totally absorbed and energy incident on surface in time $t$ be $U$ then write equation of momentum imparted to surface.
In an apparatus, the electric field was found to oscillate with an amplitude of $18 V/m. $ The magnitude of the oscillating magnetic field will be
The direction of poynting vector represents
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 $10m$ from the lamp will be........$V/m$
A laser beam can be focussed on an area equal to the square of its wavelength A $He-Ne$ laser radiates energy at the rate of $1\,mW$ and its wavelength is $632.8 \,nm$. The intensity of focussed beam will be
The oscillating magnetic field in a plane electromagnetic wave is given by $B _{ y }=5 \times 10^{-6} \sin$ $1000\,\pi\left(5 x -4 \times 10^{8} t \right) T$. The amplitude of electric field will be.