Which quantity among the following has neither units nor dimensions?

Which of the following quantities has a unit but is dimensionless?

If the unit of force and length each be increased by four times,then the unit of energy is increased by $...$ times.

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

$LIST$-$I$	$LIST$-$II$
$(A)$ Surface tension	$(I)$ $kg m^{-1} s^{-1}$
$(B)$ Pressure	$(II)$ $kg m s^{-1}$
$(C)$ Viscosity	$(III)$ $kg m^{-1} s^{-2}$
$(D)$ Impulse	$(IV)$ $kg s^{-2}$

Choose the correct answer from the options given below:

The phenomenon of physics that deals with the constitution and structure of matter at the minute scales of atoms and nuclei is

The density of a material in $CGS$ system of units is $4 \, g \, cm^{-3}$. In a system of units in which the unit of length is $10 \, cm$ and the unit of mass is $100 \, g$,the value of the density of the material will be: