Question

The acceleration due to gravity at a place can be determined with the help of a simple pendulum. For this purpose effective length of the pendulum is considered. If ${}^{\prime }{l}^{\prime }$ be the length of the string and ${}^{\prime }{d}^{\prime }$ the diameter of the bob then the effective length is equal to:

• A. $l+d$
• B. $l+\frac{d}{2}$
• C. $l-\frac{d}{2}$
• D. $l-d$

Answer 1

Answer: (B)

$l+\frac{d}{2}$

Effective length of the simple pendulum is equal to the distance of centre of mass of the bob from the point of suspension of the string with a hook.

Thus effective length of the pendulum $L^{\prime }=OB=OA+AB$

$⟹L^{\prime }=l+\frac{d}{2}$