Oscillation - NEET Physics Questions
← All Chapters

Oscillation

Question 71: easy

Time period of a second’s pendulum is \(2\text{ s}\), the approximate length of its string is equal to (\(g = 10\text{ m/s}^2\))

1. \(2\text{ m}\)
2. \(1\text{ m}\)
3. \(\frac{1}{3}\text{ m}\)
4. \(\pi\text{ m}\)
View Answer

The time period of a simple pendulum is \(T = 2\pi \sqrt{\frac{l}{g}}\). For a second's pendulum, \(T = 2\text{ s}\). Thus, \(2 = 2\pi \sqrt{\frac{l}{10}} ⇒ 1 = \pi^2 \frac{l}{10}\). Since \(\pi^2 \approx 10\), we find \(l \approx 1 \text{ m}\).

Question 72: easy

A particle moves according to equation, \(x = a \cos \frac{\pi t}{2}\) . The distance covered by it in the time interval between t = 0 to t = 3 s is

1. \(2a\)
2. \(3a\)
3. \(4a\)
4. \(a\)
View Answer

The time period is \(T = \frac{2\pi}{\omega} = \frac{2\pi}{\pi/2} = 4\text{ s}\). In \(t = 3\text{ s}\) (which is \(\frac{3T}{4}\)), the particle completes three quarters of an oscillation, covering a total distance of \(3a\).

Question 73: easy

The differential equation of motion of a particle executing SHM is \(\frac{d^2y}{dt^2} + Ky = 0\) where K is positive constant. The time period of the oscillation is given by

1. \(\frac{2\pi}{K}\)
2. \(2\pi K\)
3. \(\frac{2\pi}{\sqrt{K}}\)
4. \(2\pi\sqrt{K}\)
View Answer

Comparing with the standard equation of SHM, \(\frac{d^2y}{dt^2} + \omega^2 y = 0\), we get \(\omega = \sqrt{K}\). Therefore, the time period is \(T = \frac{2\pi}{\omega} = \frac{2\pi}{\sqrt{K}}\).

Question 74: easy

The displacement of a harmonic oscillator is given by \(x = \alpha \sin\omega t + \beta \cos\omega t\). The amplitude of the oscillation is

1. \(\alpha + \beta\)
2. \(\alpha^2 + \beta^2\)
3. \(\sqrt{\alpha^2 + \beta^2}\)
4. \(\sqrt{\alpha^2 + \beta^2 + 2\alpha\beta}\)
View Answer

Since the two perpendicular components have a phase difference of \(\frac{\pi}{2}\), the net amplitude is \(A = \sqrt{\alpha^2 + \beta^2}\).

Question 75: easy

A body is vibrating with SHM of amplitude \(15\text{ cm}\) and frequency \(4\text{ Hz}\). The maximum value of acceleration is

1. \(10.65\text{ m s}^{-2}\)
2. \(80.52\text{ m s}^{-2}\)
3. \(94.65\text{ m s}^{-2}\)
4. \(68.52\text{ m s}^{-2}\)
View Answer

The maximum acceleration is given by \(a_{\text{max}} = \omega^2 A = (2\pi f)^2 A\). Substituting \(f = 4\text{ Hz}\) and \(A = 0.15\text{ m}\) gives \(a_{\text{max}} = 4\pi^2 (16)(0.15) \approx 94.65\text{ m/s}^2\).

Question 76: easy

The differential equation of motion of a particle executing SHM is \(\frac{d^2y}{dt^2} + Ky = 0\) where \(K\) is positive constant. The time period of the oscillation is given by

1. \(\frac{2\pi}{K}\)
2. \(2\pi K\)
3. \(\frac{2\pi}{\sqrt{K}}\)
4. \(2\pi\sqrt{K}\)
View Answer

Comparing with the standard equation \(\frac{d^2y}{dt^2} + \omega^2 y = 0\), we find \(\omega = \sqrt{K}\). Thus, the time period is \(T = \frac{2\pi}{\omega} = \frac{2\pi}{\sqrt{K}}\).

Question 77: easy

A simple pendulum hanging freely stayed at rest in vertical, because in this position

1. Potential energy is maximum
2. Kinetic energy is minimum
3. Potential energy is minimum
4. Net force acting is towards point of suspension
View Answer

A stable equilibrium state corresponds to a local minimum of the system's potential energy. For a simple pendulum, the lowest point is the vertical position, where potential energy is minimum.