Question

If the time period of oscillation of a pendulum is measured as $2.5s$ using a stop watch with the leastcount $\frac{1}{2}s$, then the permissible error in the measurement is

• A. $10$%
• B. $30$%
• C. $15$%
• D. $25$%
• E. $20$%

Answer 1

The correct option is E $20$%

We have, $\frac{\Delta t}{t}=\frac{0.5}{2.5}=\frac{1}{5}$
$\frac{\Delta t}{t}$% $=\frac{1}{5}\times 100=20$%