In a new system of units, the unit of mass is 100 g, unit of length is 4 m and unit of time is 2 s. The numerical value of 10 J in this system is ________

$\begin{array}{l}\left[\text{ Energy }\right]=M{L}^2{T}^{-2}\\ \text{ In new system }\\ \begin{array}{rl} & 1\text{ unit of energy }\\ & =\frac{\left(1\text{ unit mass }\right)(\text{ 1 unit length }{)}^2}{(1\text{ unit time }{)}^2}=\frac{\left(\frac{100}{1000}\mathrm{kg}\right)(4\mathrm{m}{)}^2}{(2\sec {)}^2}\end{array}\end{array}$

$=\frac{4}{10}{\mathrm{kgm}}^2/{\mathrm{s}}^2=\frac{4}{10}\mathrm{J}$

$\text{ Now }\frac{4}{10}\mathrm{J}=1\text{ unit energy in new system }$

$\text{⇒1J=}\frac{10}{4}\text{unit energy in new system}$

$\Rightarrow 10\mathrm{J}=\frac{100}{4}\text{ unit }=25\text{ units }$