What is Resonance- Types and Applications

Resonance

Definition:      “When a periodic force is applied on a vibrating body such that the frequency of the applied force becomes equal to the natural frequency of oscillating or vibrating body, then there is an increase in the amplitude of the vibrating body. These phenomenon is called as resonance”.

        i.            Under resonance condition, the energy supplied by the driving force is just sufficient to overcome friction in the system.
      ii.            Resonance occurs when the frequency of the applied periodic force is an integral multiple of the natural frequency of a body, then the resonance take place at;

                f₂ = 2f₁

                f₃= 3f₁

                .

                .

                .

                f_n = nf₁

    iii.            In resonance situation, even the small driving force causes the amplitude of motion extraordinary large.  

Resonant Frequency

A resonant frequency is the natural vibrating frequency of an object and is usually denoted as f with a subscript zero (f₀).

Resonance is witnessed in objects that is in equilibrium with acting forces and could keep vibrating for a long time under perfect conditions.

To find the resonant frequency of a single continuous wave, we use the formula 

    v = fλ            f = v/λ  

Where,

v is the wave velocity

λ is the distance of the wavelength

Types of Resonance

There are many types of resonance, and they are:

Mechanical Resonance

Mechanical resonance can be defined as the tendency of a mechanical system to respond at greater amplitude when the frequency of its oscillations matches the system’s natural frequency of vibration (its resonance frequency or resonant frequency) than it does at other frequencies. The resonant frequency of a spring is calculated using the given formula:

            

Electrical Resonance

In a circuit when the inductive reactance and the capacitive reactance are equal in magnitude electrical resonance occurs. The resonant frequency in an LC circuit (Inductive-Capacitive circuit) is given by the formula:

        

Acoustic Resonance

Acoustic resonance is a phenomenon in which an acoustic system amplifies sound waves whose frequency matches one of its own natural frequencies of vibration. Acoustic resonance is an important consideration for instrument builders as most acoustic instruments such as the length of tube in a flute, the strings and body of a violin and the shape of a drum membrane use resonators. Acoustic resonance is also important for hearing.

Applications of Resonance:

        i.            It is used to find the natural frequency of the different bodies.
      ii.            It is used to determine the speed of sound with resonance tube apparatus.
    iii.            Resonance can be used to determine the frequency of a given body.
    iv.            Mechanical and electrical systems shows a good response under phenomenon of resonance.
      v.            Magnetic resonance imaging has greatly improved medical diagnosis.
    vi.            Cooking of foods in microwave oven is due to resonance.
  vii.            Radio receiver works on the principle of resonance.