Which of the following is not a unit of energy
$W{\rm{ - s}}$
$kg{\rm{ - }}m/\sec $
$N{\rm{ - }}m$
Joule
Which is not a unit of electric field
The unit of potential energy is
The units of angular momentum are
The unit of surface tension in $SI$ system is
If the unit of length and force be increased four times, then the unit of energy is