Question

If the value of atmospheric pressure is ${10}^{6}dynec{m}^{-2}$, then its value in SI units is:

• A. ${10}^{4}N{m}^{-2}$
• B. ${10}^{6}N{m}^{-2}$
• C. ${10}^{5}N{m}^{-2}$
• D. ${10}^{3}N{m}^{-2}$

Answer 1

The correct option is C ${10}^{5}N{m}^{-2}$

Pressure = $\frac{F}{A}$
Taking dimensions on both sides
$\left[P\right]=\frac{\left[ML{T}^{-2}\right]}{\left[L^2\right]}=\left[M{L}^{-1}{T}^{-2}\right]$
${10}^6\times {\left[\frac{1g}{1kg}\right]}^1{\left[\frac{1cm}{1m}\right]}^{-1}{\left[\frac{1s}{1s}\right]}^{-2}={10}^5$
$\therefore {10}^{6}dynec{m}^{-2}={10}^{5}N{m}^{-2}$