Which one of the following does represent the electric field lines for the $$T{E_{02}}$$ mode in the cross-section of a hollow rectangular metallic waveguide?

Two identical and parallel dipole antennas are kept apart by a distance $$\lambda /4$$ of in the H-plane. They are fed with equal currents but the right most antenna has a phase shift of +90°. The radiation pattern is given as

The primary reason for the widespread use of Silicon in semiconductor device technology is

A Silicon PN junction at a temperature of 20°C has a reverse saturation current of 10 pico-Amperes (pA). The reverse saturation current at 40°C for the same bias is approximately