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

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

When $$p$$-$$n$$ junction diode is forward biased then

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