A red $$LED$$ emits light at $$0.1$$ watt uniformly around it. The amplitude of the electric field of the light at a distance of $$1$$ $$m$$ from the diode is :

A signal of $$5$$ $$kHz$$ frequency is amplitude modulated on a carrier wave of frequency $$2$$ $$MHz.$$ The frequencies of the resultant signal is/are :

As an electron makes a transition from an excited state to the ground state of a hydrogen - like atom/ion :

Match List - $${\rm I}$$ (Fundamental Experiment) with List - $${\rm II}$$ (its conclusion) and select the correct option from the choices given below the list: