In Physics, oscillation is a repetitive variation, typically in time. It is measured between two or more different states or about equilibrium or about a central value. Some familiar examples of oscillations include alternating current and simple pendulum. Some parameters governing oscillation are :
- Period of oscillation
- Oscillation frequency
- Oscillation amplitude
In general, an oscillation is a back and forth movement in a regular rhythm. In this article, let us discuss oscillation in detail.
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Table of Contents |
Definition of Oscillation
Oscillation is the regular variation in position or magnitude about a central point or about a mean position.
The commonly used unit for the number of oscillations per second is the Hertz. Oscillations in Physics are quantified using parameters such as – Frequency, Amplitude, and period. Each term is explained as follows-
| The time taken for one complete oscillation is called the period of oscillation. | T | ||
| The number of cycles/oscillations per second is called the frequency of oscillation. | f | ||
| The maximum displacement from the mean position is called the amplitude of oscillation. | A |
How Is Oscillation Calculated?
The formula for parameters governing oscillations in Physics is listed below-
- Period of oscillation: The time period of a simple pendulum can be mathematically expressed as
\(\begin{array}{l}T=2\pi \sqrt{\frac{L}{g}}\end{array} \)Where,
T is the time period of oscillation
L is the length
g is the acceleration due to gravity - Oscillation frequency: Mathematically expressed as –
\(\begin{array}{l}f=\frac{1}{T}\end{array} \)Where,
T is the time period of oscillation.
Read More: Simple Pendulum
Examples of Oscillation
Did you know that the vibration of a guitar string is an example of oscillation? The motions of a playground swing, and tuning forks are also examples of oscillatory motion. Since these are mechanical in nature, they are also called vibrations. The motion of alternating current (although electrical) is also an example of oscillatory motion.
You may also want to check out these topics given below!
- Coefficient Of Static Friction
- Electromagnetic Damping
- Propagation Constant of a Wave
- Polarisation By Scattering
Simple Harmonic Motion
It is the simplest form of oscillatory motion that all of us come across in our day-to-day life. It is an oscillatory motion in which retarding force is proportional to the amount of displacement of an object from an equilibrium position. Or in other words, the restoring force acts in the direction opposite to that of displacement of the object and is proportional to it.
Again, the motion of a simple pendulum is a perfect example of this, where if it is displaced in one direction, the restoring force acts in the opposite direction. Any simple harmonic motion can be categorized into three types of oscillation.
Read More: Simple Harmonic Motion
Watch the video and learn more about angular SHM
Different Types of Oscillation
There are three main types of Simple Harmonic Motion
- Damped Oscillation
- Forced Oscillation
- Free Oscillation
Free Oscillation
The free oscillation possesses constant amplitude and period without any external force to set the oscillation. Ideally, free oscillation does not undergo damping. But in all-natural systems damping is observed unless and until any constant external force is supplied to overcome damping. In such a system, the amplitude, frequency and energy all remain constant.
Damped Oscillation
The damping is the resistance offered to the oscillation. The oscillation that fades with time is called damped oscillation. Due to damping, the amplitude of oscillation reduces with time. Reduction in amplitude is the result of energy loss from the system in overcoming external forces like friction or air resistance and other resistive forces. Thus, with the decrease in amplitude, the energy of the system also keeps decreasing. There are two types of damping
- Natural Damping
- Artificial Damping
Forced Oscillation
When a body oscillates by being influenced by an external periodic force, it is called forced oscillation. Here, the amplitude of oscillation, experiences damping but remains constant due to the external energy supplied to the system.
For example, when you push someone on a swing, you have to keep periodically pushing them so that the swing doesn’t reduce.
Frequently Asked Questions – FAQs
Can a motion be oscillatory but not simple harmonic? Explain with valid reason.
Consider an example of a ball dropping from a height on a perfectly elastic surface. The type of motion involved here is oscillatory but not simple harmonic as restoring force F=mg is constant and not F∝−x, which is a necessary condition for simple harmonic motion.
What is the basic condition for the motion of a particle to be a simple harmonic motion?
What happens to the oscillation of the body in damped oscillation?
What is free oscillation?
In free oscillation, what happens to the amplitude, frequency and energy of the oscillating body?
Why is the frequency of free oscillation called natural frequency?
Name a few damping forces.
In damping oscillation, why does the oscillation decrease exponentially?
What is the damping force?
What is forced oscillation?
How does the damping affect amplitude in forced oscillation?
What is resonance?
When can resonance be observed?
What is the nature of the frequency in forced oscillation?
Can a motion be periodic and not oscillatory?
In the case of uniform circular motion, it is periodic but not oscillatory.
Hope you have understood the concept of Oscillation, what is oscillation, its definition, types of oscillation, oscillation examples, simple Harmonic motion, and its types like – Free oscillation, damped oscillation and forced oscillation along with formula, terms, symbols and SI units.
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What is the main difference between forced oscillation and damped oscillation and free oscillation?
The difference between them will be clear to you once you understand what each of these terms means:
Free oscillation is an oscillation of a body with its own natural frequency and is under no external influence other than the impulse that initiated the motion. In free oscillation, the system vibrates at its natural frequency. An example of free oscillation is a pendulum. When you hit a pendulum, it will always oscillate at the same frequency no matter how hard you hit it.
Forced Oscillation occurs when an oscillating system is driven by a periodic force that is external to the system. When an external force is exerted on the object to make it oscillate at a certain frequency or for a desired period of time the resulting oscillation is known as forced oscillation. In forced oscillation, the amplitude of the oscillation remains constant as external energy is supplied to the system. When you are on a swing, you make use of your feet to move the swing or you need someone to push the swing to maintain the motion of the swing and to avoid it from stopping.
Damped Oscillation are oscillations of the body in the presence of any external retarding force. In damped oscillation, the amplitude of the oscillation reduces with time. The reduction of the amplitude is a consequence of the energy loss from the system in overcoming external forces like friction or air resistance and other resistive forces.