Rankbit System
JEE Physics: Waves (+15.5%) | Electrostatics: Concentric Shells (-29.7%) | Modern Physics: Photoelectric Clones (+34.2%) | Mathematics: Definite Integrals (+18.1%) | Chemistry: Coordination Splitting (-11.4%) | JEE Physics: Waves (+15.5%) | Electrostatics: Concentric Shells (-29.7%) | Modern Physics: Photoelectric Clones (+34.2%) | Mathematics: Definite Integrals (+18.1%) | Chemistry: Coordination Splitting (-11.4%)

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. [cite: 1, 5] Reason (R) : Time period of a simple pendulum decreases with increasing value of acceleration due to gravity and vice-versa. [cite: 1, 5] In the light of the above statements, choose the most appropriate answer from the options given below:

Solution & Explanation

### Related Formula T = 2pisqrtfraclg ### Core Logic As altitude h increases at the top of a mountain, acceleration due to gravity g drops down according to [cite: 634, 635]: g = fracg_0 R^2(R+h)^2 Since T propto frac1sqrtg, a decreased g directly makes the time period T longer[cite: 634, 635]. ### Pattern Recognition Higher altitude implies smaller gravity field implies slower pendulum oscillations implies longer period[cite: 634, 635]. ### Chapter Mix Class 11 Physics: Oscillations Class 11 Physics: Gravitation

Reference Study Guides

More Oscillations Previous-Year Questions

Q10 2025 Energy in Simple Harmonic Motion
Two bodies A and B of equal mass are suspended from two massless springs of spring constant k_1 and k_2 , respectively. If the bodies oscillate vertically such that their amplitudes are equal, the ratio of the maximum velocity of A to the maximum velocity of B is:
  • A. sqrtfrack_1k_2
  • B. fracmathrmk_1mathrmk_2
  • C. fracmathrmk_2mathrmk_1
  • D. sqrtfrack_2k_1

Solution

### Related Formula v_max = Aomega omega = sqrtfrackm ### Core Logic The maximum velocity in vertical SHM happens at the mean equilibrium position and is given by v_max = Aomega. Given m_A = m_B = m and A_A = A_B = A: v_A = A omega_1 = A sqrtfrack_1m v_B = A omega_2 = A sqrtfrack_2m Taking the ratio: fracv_Av_B = fracomega_1omega_2 = fracsqrtfrack_1msqrtfrack_2m = sqrtfrack_1k_2 ### Pattern Recognition Since maximum velocity is directly proportional to angular frequency omega for equal amplitudes, and omega propto sqrtk, the velocity ratio directly yields the square root of the spring constant ratio. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Physics: Oscillations
Q17 2025 Simple Pendulum
Two simple pendulums having lengths l_1 and l_2 with negligible string mass undergo angular displacements theta_1 and theta_2, from their mean positions, respectively. If the angular accelerations of both pendulums are same, then which expression is correct?
  • A. theta_1l_2^2 = theta_2l_1^2
  • B. theta_1l_1 = theta_2l_2
  • C. theta_1l_1^2 = theta_2l_2^2
  • D. theta_1l_2 = theta_2l_1

Solution

### Related Formula Angular acceleration definition for a simple pendulum swinging at small angle theta: alpha = -omega^2 theta where: omega = sqrtfracgl implies omega^2 = fracgl Hence, the magnitude of angular acceleration is: alpha = fracgltheta ### Core Logic Given that angular accelerations are exactly identical in magnitude (alpha_1 = alpha_2): fracgl_1theta_1 = fracgl_2theta_2 ### Step 1: Simplify Expression Cancelling out the constant gravitational field factor g: fractheta_1l_1 = fractheta_2l_2 implies theta_1 l_2 = theta_2 l_1 ### Pattern Recognition Angular acceleration scales inversely with length for a fixed angle. To preserve equal acceleration values, the product theta cdot l^-1 must be constant, resulting in cross-multiplication balance. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Physics: Oscillations
Q19 2025 Simple Harmonic Motion Graphs
A particle oscillates along the x-axis according to the law, mathrmx(t) = mathrmx_0 sin^2left(fract2 ight) where x_0 = 1 \, m . The kinetic energy (K) of the particle as a function of x is correctly represented by the graph.
  • A. Graph (1)
  • B. Graph (2)
  • C. Graph (3)
  • D. Graph (4)

Solution

### Related Formula x(t) = x_0 sin^2left(fract2 ight) = x_0 left(frac1 - cos t2 ight) ### Core Logic Given x_0 = 1\ mathrmm, the position simplifies to: x = frac1 - cos t2 implies 2x - 1 = -cos t implies cos t = 1 - 2x Differentiating x(t) to find velocity v: v = fracdxdt = frac12sin t Kinetic energy K is proportional to v^2: K = frac12mv^2 = frac12m left(frac14sin^2 t ight) = fracm8(1 - cos^2 t) Substituting cos t = 1 - 2x: K = fracm8left[1 - (1 - 2x)^2 ight] = fracm8left[1 - (1 - 4x + 4x^2) ight] = fracm8(4x - 4x^2) = fracm2(x - x^2) This is an inverted parabola (K propto x - x^2) passing through x=0 and x=1, reaching a peak at x = 1/2. This matches Graph (1). ### Pattern Recognition The position oscillates purely within the boundary interval [0, 1]. Kinetic energy peaks perfectly at the equilibrium midpoint x = 1/2 where speed is maximum. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Physics: Oscillations
Q13 2025 Simple Harmonic Motion
A particle is executing simple harmonic motion with time period 2s and amplitude 1 cm. If D and d are the total distance and displacement covered by the particle in 12.5 s, then fracDd is:-
  • A. frac154
  • B. 25
  • C. 10
  • D. frac165

Solution

### Related Formula In Simple Harmonic Motion: * In one full oscillation period T, total distance = 4A, and net displacement = 0. * In a quarter period fracT4 starting from equilibrium, distance = A, and displacement = A. ### Core Logic Find the total number of cycles completed in the given time : textCycles = fractT = frac12.5text s2text s = 6.25text cycles = 6 text full cycles + 0.25text cycle ### Step 1: Evaluation of Distance and Displacement Calculate the total distance D covered : D = 6 times (4A) + 1A = 24A + A = 25A Given amplitude A = 1text cm , we get D = 25text cm . Calculate the net displacement d: The first 6 complete cycles return the particle to equilibrium with zero displacement. The remaining 0.25 cycle (which is a quarter period fracT4) moves it from the center to its maximum amplitude value : d = 1A = 1text cm Taking their ratio: fracDd = frac251 = 25 ### Pattern Recognition Fractional cycles modulate ratios abruptly. Always break the path index down into integer full cycles plus the final residual interval. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Physics: Oscillations
Q12 2025 Simple Harmonic Motion
Given below are two statements. One is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): Knowing initial position x_0 and initial momentum p_0 is enough to determine the position and momentum at any time t for a simple harmonic motion with a given angular frequency omega . Reason (R) : The amplitude and phase can be expressed in terms of x_0 and p_0 . In the light of the above statements, choose the correct answer from the options given below:
  • A. Both (A) and (R) are true but (R) is NOT the correct explanation of (A).
  • B. (A) is false but (R) is true.
  • C. (A) is true but (R) is false.
  • D. Both (A) and (R) are true and (R) is the correct explanation of (A).

Solution

### Related Formula The general solution tracking position in SHM is given by : x(t) = A sin(omega t + phi) Momentum formula: p(t) = m v(t) = m A omega cos(omega t + phi) ### Core Logic At t = 0 : 1) x_0 = A sin phi 2) p_0 = m A omega cos phi Dividing equation (1) by (2) reveals the phase \angle relationship : tan phi = left(fracx_0p_0right) m omega implies phi = tan^-1left(fracm omega x_0p_0right) Squaring and combining both equations isolates amplitude A: A = fracsqrt(m omega x_0)^2 + p_0^2m omega Since both amplitude A and phase constant phi are explicitly fixed by the initial conditions x_0 and p_0, the kinematic layout of the state space is completely specified for any future time parameter t. This validates that Reason (R) perfectly explains Assertion (A). ### Pattern Recognition SHM is a second-order differential equation. Any system of second-order equations requires exactly two independent boundary conditions (e.g., initial position and velocity/momentum) to completely specify unique path tracks. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Physics: Oscillations

More Oscillations Questions — jee_main_2025_29_jan_morning

Practice all Oscillations previous-year questions →

YOUR FIRST PREP STEP STARTS HERE

We Map Every Repeating Question in Competitive Exams.

Say goodbye to generic mock test fatigue. RankBit uses smart analysis to group past exam questions into their foundational Repeating Question Types. Find chapter weightage, track repeating questions, and score higher with targeted practice.

Select Your Target Exam

Choose an exam track below to find formulas per chapter and patterns.

Syncing Exam Intelligence

Mapping formulas and patterns across all tracks…

PATH A — FULL LENGTH PRACTICE

Full Mock Test Hub

Simulate real NTA exam conditions with fully tracked mocks. Time yourself against past papers.

Under Development
PATH B — TARGETED PRACTICE

Topic-wise Practice Hub

Practice past-year questions one chapter at a time. Pick an exam → subject → chapter and get every PYQ for that topic — pulled together from all past papers — with the chapter's key formulas alongside.

Loading Questions... Browse Topics
Latest from the Blog
View all →

Loading articles...