The modes in a rectangular waveguide are denoted by $$T{E_{mn}}\,$$/$$T{M_{mn}}\,$$ where m and n are the eigen numbers along the larger and smaller dimensions of the waveguide respectively. Which one of the following satements is TRUE?

Consider a closed surface S surrounding volume V. If $$\overrightarrow{\mathrm r}$$ is the position vector of a point inside S, with $$\widehat n$$ the unit normal on S, the value of the integral is

Drift current in the semiconductors depends upon

For a BJT the common base current gain $$\alpha$$ = 0.98 and the collector base junction reverse bias saturation current I_CO = 0.6μA. This BJT is connected in the common emitter mode and operated in the active region with a base drive current I_B=20μA. The collector current IC for this mode of operation is