Change set

Pick exam & year, then Go.

Question map
Not attempted Correct Incorrect Bookmarked
Loading…
Q51 (NDA-I/2026) Science & Technology › Basic Science (Physics, Chemistry, Biology)

A pendulum of length L oscillates with an angular amplitude of θ = 60° and time period T. Let T0 = 2π√(L/g) be the time period for small angle of oscillations, where g is the acceleration due to gravity. If air resistance is negligibly small and the string remains straight, then which one of the following is correct?

Result
Your answer:  ·  Correct: A

Explanation

The standard formula T0 = 2π√(L/g) is derived using the small-angle approximation, which assumes sin θ ≈ θ. This approximation is only accurate for small amplitudes (typically θ < 15°). For larger angles like θ = 60°, the restoring force is slightly less than what the linear approximation predicts, causing the pendulum to move slower and take more time to complete a cycle.

The exact period T is given by an infinite series: T = T0 [1 + (1/2)2 sin2(θ/2) + (3/8)2 sin4(θ/2) + ...]. Since the additional terms are positive, T will always be greater than T0 for any finite angle. For θ = 60°, T is approximately 7.3% greater than T0. Additionally, the period of a simple pendulum is independent of the mass of the bob, making option D incorrect.

How others answered
Each bar shows the % of students who chose that option. Green bar = correct answer, blue outline = your choice.
Community Performance
Out of everyone who attempted this question.
33%
got it right
✓ Thank you! We'll review this.

SIMILAR QUESTIONS

CAPF · 2018 · Q8 Relevance score: 3.34

If the amplitude of oscillation of a simple pendulum is very small, then iLs time period of oscillation 1. depends on the length of the pendulum, L 2. depends on the acceleration due to gravity, g 3. depends upon the mass of the bob of the pendulum, m 4. does not depend upon the amplitude of the pendulum, A Select the correct answer using the codt: given below.

NDA-II · 2018 · Q41 Relevance score: 2.48

The time period of oscillation of a simple pendulum having length L and mass of the bob m is given as T. If the length of the pendulum is increased to 4L and the mass of the bob is increased to 2m, then which one of the following is the new time period of oscillation?

NDA-II · 2022 · Q85 Relevance score: 1.12

A simple pendulum having bob of mass m and length of string l has time period of T. If the mass of the bob is doubled and the length of the string is halved, then the time period of this pendulum will be

NDA-I · 2017 · Q57 Relevance score: 0.61

The time period of a simple pendulum made using a thin copper wire of length L is T. Suppose the temperature of the room in which this simple pendulum is placed increases by 30°C, what will be the effect on the time period of the pendulum ?

NDA-II · 2019 · Q140 Relevance score: 0.35

A pendulum clock is lifted to a height where the gravitational acceleration has a certain value g. Another pendulum clock of the same length but of double the mass of the bob is lifted to another height where the gravitational acceleration is g/ 2. The time period of the second pendulum would be in terms of period T of the first pendulum