Easy MCQ +4 / -1 PYQ · JEE Mains 2025

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).

Assertion (A) : Time period of a simple pendulum is longer at the top of a mountain than that at the base of the mountain.

Reason (R) : Time period of a simple pendulum decreases with increasing value of acceleration due to gravity and vice-versa.

In the light of the above statements, choose the most appropriate answer from the options given below :

  1. A <p>Both <b>(A)</b> and <b>(R)</b> are true but <b>(R)</b> is <u>not</u> the correct explanation of <b>(A)</b>.</p>
  2. B <p><b>(A)</b> is true but <b>(R)</b> is false.</p>
  3. C <p>Both <b>(A)</b> and <b>(R)</b> are true and <b>(R)</b> is the correct explanation of <b>(A)</b>.</p> Correct answer
  4. D <p><b>(A)</b> is false but <b>(R)</b> is true.</p>

Solution

<p>$$\begin{aligned} &\text { As } h \text { increases, } g \text { decreases, } \mathrm{T} \text { increases }\\ &\begin{aligned} & \mathrm{T}=2 \pi \sqrt{\frac{\ell}{\mathrm{~g}}} \\ & \mathrm{~g}=\frac{\mathrm{g}_0 \mathrm{R}^2}{(\mathrm{R}+\mathrm{h})^2} \end{aligned} \end{aligned}$$</p>

About this question

Subject: Physics · Chapter: Oscillations · Topic: Simple Harmonic Motion

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