A nucleus disintegrated into two nuclear parts which have their velocities in the ratio of $$2:1.$$ The ratio of their nuclear sizes will be

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