The magnetic field in a plane electromagnetic wave is given by $=2 \times 10^{-7} \sin \left(0.5 \times 10^3 x+1.5 \times 10^{11} t\right)$. This electromagnetic wave is ………

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 ? 

Electromagnetic wave consists of periodically oscillating electric and magnetic vectors

The photon energy in units of $eV$ for electromagnetic wave of wavelength $2\,cm$ is

The following travelling electromagnetic wave $E_x=0$ $E_y=E_0 \sin (k x+\omega t), E_z=-2 E_0 \sin (k x-\omega t)$ is