Question

The pressure on a square plate is measured by measuring the force on the plate and the length of the sides of the plate. If the maximum error in the measurement of force and length are respectively 4% and 2%, The maximum error in the measurement of pressure is

• A. 1%
• B. 2%
• C. 6%
• D. 8%

Answer 1

Answer: (D)

8%

Answer 2

$P = \frac{F}{A} = \frac{F}{l^{2}}$, so maximum error in pressure $(P)$

${\left( \frac{\Delta P}{P} \times 100 \right)\frac{\Delta F}{F}\frac{\Delta l}{l}}_{\max}$ = 4% + 2 × 2% = 8%