Which one of the following field patterns represents a TEM wave traveling in the positive $$x$$ direction?

To maximize power transfer, a lossless transmission line is to be matched to a resistive load impedance via a $$\lambda /4$$ transformer as shown.

Assume electronic charge q = 1.6×10^-19 C, kT/q = 25 mV and electron mobility μ_n = 1000 cm²/V-s. If the concentration gradient of electrons injected into a P-type silicon sample is 1×10²¹/cm⁴, the magnitude of electron diffusion current density (in A/cm²) is _________.

Consider an abrupt PN junction (at T = 300 K) shown in the figure. The depletion region width X_n on the N-side of the junction is 0.2 µm and the permittivity of silicon (ε_si) is 1.044×10^-12 F/cm. At the junction, the approximate value of the peak electric field (in kV/cm) is _________.