In a common base amplifier, the phase difference between the input signal voltage and output voltage is

When $$npn$$ transistor is used as an amplifer

For a transistor amplifier in common emitter configuration for load impedance of $$1k\,\Omega $$ $$\left( {{h_{fe}} = 50} \right.$$ and $$\left. {{h_{oe}} = 25} \right)$$ the current gain is

A piece of copper and another of germanium are cooled from room temperature to $$77K,$$ the resistance of