Question

Thickness of a pencil measured by using a screw gauge (least count .$001cm$) comes out to be $0.802cm$. The percentage error in the measurement is :

• A. $0.125\%$
• B. $2.43\%$
• C. $4.12\%$
• D. $2.14\%$

Answer 1

Answer: (A)

$0.125\%$

Least count screw gause is $=0.001cm$

The error will be thickness, $t=0.802\pm 0.001$

$\Delta t$ is $0.001cm$

Percentage error $=\frac{\Delta t}{t}\times 100\%$

Percentage error $=\frac{0.001}{0.802}\times 100\%$

Percentage error $=0.125\%$