Question

If the value of atmospheric pressure is 10⁶ dyne cm^-2, its value in SI units is

• A. 10⁴ N m^-2
• B. 10⁶ N m^-2
• C. 10⁵ N m^-2
• D. 10³ N m^-2

Answer 1

Answer: (C)

10⁵ N m^-2

Answer 2

Pressure $= \frac{F}{A}$ Takings dimensions on both sides

$\lbrack P\rbrack = \frac{\lbrack MLT^{- 2}\rbrack}{\lbrack L^{2}\rbrack} = \lbrack ML^{- 1}T^{- 2}\rbrack 10^{6} = \left\lbrack \frac{1g}{1kg} \right\rbrack^{1}\left\lbrack \frac{1cm}{1m} \right\rbrack^{- 1}\left\lbrack \frac{1s}{1s} \right\rbrack^{- 2} = 10^{5}\therefore 10^{6}dynecm^{- 2} = 10^{5}Nm^{- 2}.$