NDA2025General AbilityGeneral ScienceActual
The length of a simple pendulum is increased four times to its previous value while the mass is doubled. What is the ratio of the new and previous time period of the pendulum?
Options
- A3 : 1
- B2 : 5
- C2 : 1
- D3 : 2
Correct answer
C. 2 : 1
Step-by-step solution
The time period of a simple pendulum is given by T = 2 l g . The time period is independent of the mass of the bob. Given that the new length is l₂ = 4l₁ . The new time period is T₂ = 2 l₂ g = 2 4l₁ g = 2 2 l₁ g = 2T₁ . The ratio of the new and previous time period is T₂ T₁ = 2 1 . Answer: 2 : 1