The displacement of a particle, executing simple harmonic motion with time period T, is expressed as x(t) = A sin omega t , where A is the amplitude. The maximum value of potential energy of this oscillator is found at t = T/2beta . The value of beta is ____.

Numerical Answer Type:
Enter a numerical value Answer: 2 to 2 +4 marks

Solution & Explanation

### Related Formula PE = frac12 k x^2 PE_textmax occurs when x = pm A. ### Core Logic Potential energy is maximum at the extreme positions. From x(t) = A sin(omega t), the particle starts at the mean position (x=0 at t=0) and reaches the extreme position (x=A) for the first time at t = T/4. ### Step 1: Finding beta Given time for maximum PE is t = fracT4. We are given t = fracT2beta. Therefore, fracT4 = fracT2beta Rightarrow 2beta = 4 Rightarrow beta = 2. ### Pattern Recognition Sine function SHM starts at mean, hits extreme at T/4, back to mean at T/2, negative extreme at 3T/4, back to mean at T. PE is max at T/4 and 3T/4. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Physics: Oscillations

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More Oscillations Previous-Year Questions

Q33 jee_main_2026_21_jan_evening Simple Harmonic Motion
The kinetic energy of a simple harmonic oscillator is oscillating with angular frequency of 176 text rad/s. The frequency of this simple harmonic oscillator is ________ Hz. [texttake pi = frac227]
  • A. 14
  • B. 88
  • C. 28
  • D. 176

Solution

### Related Formula omega_k = 2pi f_k f_textoscillator = fracf_k2 ### Core Logic For a simple harmonic oscillator with an angular frequency omega, the kinetic energy oscillates at double the angular frequency (2omega). The given angular frequency of kinetic energy oscillation is omega_k = 176 text rad/s. ### Step 1: Finding Kinetic Energy Frequency First, find the frequency of kinetic energy oscillations (f_k): f_k = fracomega_k2pi = frac1762 times frac227 f_k = frac176 times 744 = 4 times 7 = 28 text Hz ### Step 2: Final Conclusion Since kinetic energy oscillates at twice the frequency of the oscillator itself: f_textoscillator = fracf_k2 = frac282 = 14 text Hz ### Pattern Recognition KE and PE always oscillate at twice the frequency (2nu) of the underlying SHM (v) due to the sin^2(omega t) or cos^2(omega t) terms resolving to (1 - cos(2omega t))/2. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Physics: Oscillations
Q31 jee_main_2026_23_january_morning Simple Pendulum
A simple pendulum of string length 30 cm performs 20 oscillations in 10s. The length of the string required for the pendulum to perform 40 oscillations in the same time duration is ____ cm. [Assume that the mass of the pendulum remains same.]
  • A. 120
  • B. 0.75
  • C. 7.5
  • D. 15

Solution

### Related Formula T = 2pi sqrtfraclg T propto sqrtl ### Core Logic For a simple pendulum, the period is proportional to the square root of the length. If the frequency is doubled, the period is halved, which requires the length to become one-fourth of its original value. ### Step 1: Find Old and New Period Initial time period T_1 = frac1020 = 0.5 text s New time period T_2 = frac1040 = 0.25 text s So, T_2 = fracT_12 ### Step 2: Calculate New Length fracT_1T_2 = sqrtfracl_1l_2 2 = sqrtfrac30l_2 4 = frac30l_2 l_2 = frac304 = 7.5 text cm ### Pattern Recognition Sees: "Oscillations doubled in same time" → Frequency is doubled → Time period is halved. Since T propto sqrtl, l must be reduced to frac14 of the original. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Physics: Oscillations
Q28 jee_main_2026_24_january_morning Simple Harmonic Motion
A cylindrical block of mass M and area of cross section A is floating in a liquid of density rho and with its axis vertical. When depressed a little and released the block starts oscillating. The period of oscillation is ____.
  • A. 2pisqrtfracMrho Ag
  • B. pi sqrtfrac2mathrmMrhomathrmAg
  • C. pi sqrtfracrhomathrmAmathrmMg
  • D. 2pi sqrtfracrho AMg

Solution

### Related Formula T = 2pi sqrtfracMk_texteffective F_textbuoyancy = rho V g ### Core Logic
Floating cylindrical block in liquid
Floating cylindrical block in liquid
At equilibrium, the buoyant force balances the weight: rho Ahg = Mg After displacing the block downward by a small distance x, the net restoring force is: Ma = -rho A(h+x)g + Mg Ma = -rho Ahg - rho Axg + Mg Since rho Ahg = Mg, this simplifies to: Ma = -rho Axg a = left(frac-rho AgMright) x ### Step 1: Compare with Standard SHM Equation Comparing with a = -omega^2 x, we get: omega = sqrtfracrho AgM The time period T is: T = frac2piomega = 2pi sqrtfracMrho Ag ### Pattern Recognition For a floating body of uniform cross-section A, the restoring force constant is simply k = rho A g. The time period is immediately T = 2pi sqrtm/k. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Physics: Oscillations Class 11 Physics: Mechanical Properties of Fluids
Q42 jee_main_2026_28_january_evening Two Body Oscillator
As shown in the figure, a spring is kept in a stretched position with some extension by holding the masses 1 text kg and 0.2 text kg with a separation more than spring natural length and are released. Assuming the horizontal surface to be frictionless, the angular frequency (in SI unit) of the system is :
Two Body Oscillator diagram for Q42 - JEE Main 2026 Evening
Two masses attached to ends of a spring on a horizontal table.
  • A. 30
  • B. 27
  • C. 20
  • D. 5

Solution

### Related Formula omega = sqrtfrackmu where mu is the reduced mass of the system given by: mu = fracm_1 m_2m_1 + m_2 ### Step 1: Calculate Reduced Mass Given m_1 = 1 text kg and m_2 = 0.2 text kg. mu = frac1 times 0.21 + 0.2 = frac0.21.2 mu = frac16 text kg ### Step 2: Calculate Angular Frequency Given spring constant k = 150 text N/m. omega = sqrtfrac1501/6 = sqrt150 times 6 = sqrt900 omega = 30 text rad/s ### Pattern Recognition For any two-body spring system free of external forces, always substitute the individual mass m with the reduced mass mu = fracm_1 m_2m_1 + m_2 in the standard oscillator formula omega = sqrtk/m. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Physics: Oscillations

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