Which of the following are not electromagnetic waves?

Match List-$I$ with List-$II$:

List-$I$	List-$II$
$(a)$ Ultraviolet rays	$(i)$ Study crystal structure
$(b)$ Microwaves	$(ii)$ Greenhouse effect
$(c)$ Infrared waves	$(iii)$ Sterilizing surgical instruments
$(d)$ $X$-rays	$(iv)$ Radar system

Choose the correct answer from the options given below:

In household appliances,which waves are used to operate remote control switches?

Practically,the ozone layer absorbs radiations of wavelength:

The power of a source is $4 \, kW$. If it produces $10^{20}$ photons in $1 \, s$,then the radiation emitted from this source belongs to which part of the electromagnetic spectrum?

Which of the following electromagnetic waves have the minimum frequency?