An $\alpha$-particle of energy $E$ is liberated during the decay of a nucleus of mass number 236. The total energy released in this process is

The voltage gain of a transistor in common emitter configuration is 160 . The resistances in base and collector sides of the circuit are $1 \mathrm{k} \Omega$ and $4 \mathrm{k} \Omega$ respectively. If the change in base current is $100 \mu \mathrm{~A}$, then the change in output current is

Normally a capacitor is connected across the output terminals of a rectifier to

The process of the loss of strength of a signal while propagating through a medium is