Question

If the length of rod $A$ is $3.25\pm 0.01\,cm$ and that of $B$ is $4.19\pm 0.01\,cm,$ then the rod $B$ is longer than rod $A$ by

• A. $0.94\pm 0.00\,cm$
• B. $0.94\pm 0.01\,cm$
• C. $0.94\pm 0.02\,cm$
• D. $0.94\pm 0.005\,cm$

Answer 1

Answer: (C)

$0.94\pm 0.02\,cm$

Answer 2

Length of rod $A$ is
$L_A = 3.25 \pm 0.01$
and that of $B$ is
$L_B = 4.19 \pm 0.01$
Then, the rod $B$ is longer than rod $A$ by a length
$\triangle l = L_B - L_A$
$\triangle l = ( 4.19 \pm 0.01) - ( 3.25 \pm 0.01)$
$\triangle l = ( 0.94 \pm 0.02 ) cm$