Question

If the length of simple pendulum is increased by 300%, then the time period will be increased by

• A. 100%
• B. 200%
• C. 300%
• D. 400%

Answer 1

Answer: (A)

100%

Answer 2

$\frac{T_{1}}{T_{2}} = \sqrt{\frac{l_{1}}{l_{2}}} \Rightarrow \frac{T_{1}}{T_{2}} = \sqrt{\frac{100}{400}}$ (If $l_{1} = 100$ then $l_{2} = 400$)

$\Rightarrow$ $T_{2} = 2T_{1}$

Hence % increase $= \frac{T_{2} - T_{1}}{T_{1}} \times 100 = 100\%$