In a simple pendulum experiment to determine the acceleration due...

The formula for the acceleration due to gravity $g$ using a simple pendulum is:
$g = \dfrac{4 \pi^2 L}{T^2}$

Since the time for $n$ oscillations is $t = nT$, we can write $T = \dfrac{t}{n}$. Substituting this into the formula gives:
$g = \dfrac{4 \pi^2 n^2 L}{t^2}$

The maximum fractional error in $g$ is:
$\dfrac{\Delta g}{g} = \dfrac{\Delta L}{L} + 2\dfrac{\Delta t}{t}$

The absolute errors are taken as the least counts of the respective measuring instruments:
$\Delta L = 1 \text{ mm} = 0.1 \text{ cm}$
$\Delta t = 0.1 \text{ s}$

Now, calculating the individual percentage errors:
Percentage error in $L = \left(\dfrac{0.1}{10.0}\right) \times 100 = 1\%$
Percentage error in $t = \left(\dfrac{0.1}{20.0}\right) \times 100 = 0.5\%$

Substituting these into the error equation:
Maximum percentage error in $g = 1\% + 2(0.5\%) = 1\% + 1\% = 2\%$

Answer: 2