Question

A force F is applied on a square plate of side L. If percentage error in determination of L is 2% and that in F is 4%, permissible error in pressure is

• A. 0.02
• B. 0.04
• C. 0.06
• D. 0.08

Answer 1

Answer: (D)

0.08

Answer 2

Pressure = $\frac{ force }{ area } = \frac{ F }{ L^2 }$
$\therefore \frac{ dp }{ p } \times 100 = \bigg( \frac{ dF }{ F } + \frac{ 2 dL }{ L} \bigg) \times 100$
= 4 + 2 $\times$ 2 = 8%