Physics Electromagnetic Waves

Choose the correct option relating wavelengths of different parts of electromagnetic wave spectrum:

Choose the correct option relating wavelengths of different parts of electromagnetic wave spectrum:

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:

A wire of length 25 m and cross-sectional area 5 mm² having resistivity of 2 × 10⁻⁸ Ω m is bent into a complete circle. The resistance between diametrically opposite points will be

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: