A long straight wire with a circular cross-section having radius R, is carrying a steady current I. The current I is uniformly distributed across this cross-section. Then the variation of magnetic field due to current I with distance r (r < R) from its centre will be :

If wattless current flows in the AC circuit, then the circuit is :

The electric field in an electromagnetic wave is given by E = 56.5 sin $$\omega$$(t $$-$$ x/c) NC^$$-$$1. Find the intensity of the wave if it is propagating along x-axis in the free space.

(Given : $$\varepsilon $$₀ = 8.85 $$\times$$ 10^$$-$$12C²N^$$-$$1m^$$-$$2)

The two light beams having intensities I and 9I interfere to produce a fringe pattern on a screen. The phase difference between the beams is $$\pi$$/2 at point P and $$\pi$$ at point Q. Then the difference between the resultant intensities at P and Q will be :