In order to measure physical quantities in the sub-atomic world, the quantum theory often employs energy [E]…
- $\frac{[\mathrm{E}]^{4}}{[\mathrm{~J}]^{3}[\mathrm{c}]^{3}}$
- $\frac{[\mathrm{E}]^{2}}{[\mathrm{~J}][\mathrm{c}]}$
- $\frac{[\mathrm{E}]}{[\mathrm{J}]^{2}[\mathrm{c}]^{2}}$
- $\frac{[\mathrm{E}]^{3}}{[\mathrm{~J}]^{2}[\mathrm{c}]^{2}}$
Solution
$[\mathrm{J}]=\left[\mathrm{ML}^{2} \mathrm{~T}^{-1}\right]$
(ii) $\ldots . .$ (i
$[\mathrm{C}]=\left[\mathrm{LT}^{-1}\right]$
(iii) Solving (i), (ii) and (iii) we get,
$\left[\frac{\mathrm{E}}{\mathrm{C}^{2}}\right]=[\mathrm{M}], \quad\left[\frac{\mathrm{JC}}{\mathrm{E}}\right]=[\mathrm{L}]$ and $\left[\frac{\mathrm{J}}{\mathrm{E}}\right]=[\mathrm{T}]$
Now, [Pressure] $=\left[\mathrm{ML}^{-1} \mathrm{~T}^{-2}\right]$
$=\left[\frac{\mathrm{E}}{\mathrm{C}^{2}}\right] \times\left[\frac{\mathrm{E}}{\mathrm{JC}}\right] \times\left[\frac{\mathrm{E}^{2}}{\mathrm{~J}^{2}}\right]=\frac{[\mathrm{E}]^{4}}{\left[\mathrm{~J}^{3}\right]\left[\mathrm{C}^{3}\right]}$ .
Asked in: JEE Mains - Units and Dimensions - Test 1