To find the value of g using simple pendulum, $T=2.0 \mathrm{s}$, $l=1.0 \mathrm{m}$. The value of g is ( Take. ${\pi }^2=10$ )

$T=2\pi \sqrt{\frac{l}{g}}$

$g=\frac{4{\pi }^{2}l}{T^2}$

$\frac{\Delta \mathrm{g}}{\mathrm{g}}=\frac{\Delta l}{l}+2\frac{\Delta T}{T}$

$=\frac{0.01}{1.00}+\frac{2\times 0.01}{200}$

$=0.01+0.01=0.02$

Percentage error in $g=\frac{\Delta g}{g}\times 100$

$=0.02\times 100=2\%$

$g=\frac{4{\pi }^{2}l}{T^2}=\frac{4\times 10\times 1}{(2{)}^2}$

$=\frac{40}{4}=10{ \mathrm{ms}}^{-2}$

$g=(10\pm 2\%)m{s}^{-2}$