Using a simple pendulum experiment, g is determined by measuring its time period T. Which of the following plots represents the correct relation between pendulum length ℓ and time period T?

Solution:

For a simple pendulum:

T = 2π√(ℓ/g)

Squaring both sides:

T² ∝ ℓ

Hence, the graph between ℓ and T² is a straight line passing through the origin.

Answer: T² is directly proportional to ℓ.