Physics Electromagnetic Waves

The electric field of a plane electromagnetic wave propagating along the $x$  direction in vacuum is $\vec{E}=E_0\hat{j}\mathrm{c}\mathrm{o}\mathrm{s}(\omega t-kx)$   . The magnetic field $\vec{B}$ , at the moment   $t=0$ is:

In a plane electromagnetic wave, the directions of electric field and magnetic field are represented by k̂ and 2î – 2ĵ, respectively. What is the unit vector along direction of propagation of the wave.

A capillary tube made of glass of radius 0.15 mm is dipped vertically in a beaker filled with methylene iodide (surface tension = 0.05 Nm⁻¹, density = 667 kg m⁻³) which rises to height h in the tube. It is observed that the two tangents drawn from liquid-glass interfaces (from opposite sides of the capillary) make an angle of 60° with one another. Then h is close to (g = 10 ms⁻²)

Magnitude of magnetic field (in SI units) at the centre of a hexagonal shape coil of side 10 cm, 50 turns and carrying current I (Ampere) in units of µ?I/π is:

A plane electromagnetic wave, has frequency of 2.0 * 10¹⁰ Hz and its energy density is 1.02 * 10⁻⁸ J/m³ in vacuum. The amplitude of the magnetic field of the wave is close to (1/(4πε₀) = 9 * 10⁹ Nm²/C² and speed of light = 3 * 10⁸ ms⁻¹):

Suppose that intensity of a laser is (315/π) W/m². The rms electric field, in units of V/m associated with this source is close to the nearest integer is (ε₀ = 8.86 * 10⁻¹² C²N⁻¹m⁻²; c = 3 * 10⁸ ms⁻¹)

The quantities x = 1/√(µ₀ε₀), y = E/B and z = 1/CR are defined where C-capacitance, R Resistance, l-length, E-Electric field, B-magnetic field and ε₀, µ₀, - free space permittivity and permeability respectively. Then: