If the unit of length, mass and time be each doubled, then the unit of work will **Doubled.**

**Explanation —**

$\text { work }=\left[ ML ^{2} T ^{-2}\right]$

$\frac{ U _{2}}{ U _{1}}=\frac{ M _{2}}{ M _{1}}\left[\frac{ L _{2}}{ L _{1}}\right]^{2}\left[\frac{ T _{2}}{ T _{1}}\right]^{-2}$

$=\left[\frac{2 M _{1}}{ M _{1}}\right]\left[\frac{2 L _{1}}{ L _{1}}\right]^{2}\left[\frac{2 T _{1}}{ T _{1}}\right]^{-2}$

$=2 \times 2^{2} \times 2^{-2}=2 \text { hence, } U _{2}=2 U _{1}$