Consider a wireless communication link between a transmitter and a receiver located in free space, with finite and strictly positive capacity. If the effective areas of the transmitter and the receiver antennas, and the distance between them are all doubled, and everything else remains unchanged, the maximum capacity of the wireless link

An optical fiber is kept along the$$\widehat Z$$ direction. The refractive indices for the electric fields along $$\widehat X$$ and $$\widehat Y$$ directions in the fiber are $${n_x} = 1.5000$$ and $${n_y} = 1.5001$$, respectively ($${n_x} \ne {n_y}$$ due to the imperfection in the fiber cross-section). The free space wavelength of a light wave propagating in the fiber is $$1.5\,\,\,\mu m$$. If the light wave is circularly polarized at the input of the fiber, the minimum propagation distance after which it becomes linearly polarized, in centimeters, is _______ .

A bar of Gallium Arsenide (GaAs) is doped with Silicon such that the Silicon atoms occupy Gallium and Arsenic sites in the GaAs crystal. Which one of the following statement is true?

The dependence of drift velocity of electrons on electric field in a semiconductor is shown below. The semiconductor has a uniform electron concentration of n = 1x10¹⁶ $$cm^{-3}$$ and electronic charge q = 1.6x10^-19 C. If a bias of 5V is applied across a 1 $$\mu$$m region of this semiconductor, the resulting current density in this region, in kA/cm², is _________.