Anything we hear around us is not is sound but vibration of particles. Vibration is a type of disturbance which propagates by particles of medium.

Sound is not travel but it is a wave that is transferred by particles in the form of vibrations (particles can only transfer the vibrations by one particle to second and 2nd to 3rd and so on by remain their positions).

Without particles, sound has no existence. Sound not travel in space because there are no particles in space. , so we transfer the information in form of signal in space.

Speed of sound in different mediums

Air – 343m/sec

Water – 1437m/sec

Glass – 4540m/sec

Iron – 5120m/sec

According to this, as the medium density increases sound speed also increases.

Effect of temperature- As temperature increases speed of sound increases.

The normal range of sound to hear anything for human is 20hz to 20000hz.

But minimum range of sound which a human can hear is 12hz and maximum is 28000hz.

The sound created by a volcano eruption in 1883 is in range of 180decibel and it can be heard up to 3000 miles (ca. 4,828 km).

the sound created by the explosion of nuclear bomb is in range of 240 to 280+ decibels.

So, we cannot imagine what will be the loudest sound.


Light energy is a traveling Photon which is a form of electromagnetic radiation. Photon is a bundle of energy. 

Speed of light is 3 × 10⁸m/sec. in vacuum. 

As dense as the medium the speed of light will decrease.

Nature of light-

Light has dual nature

1- wave nature- we consider the light have wave nature because light has the property of diffraction, refraction, and interference etc.

2-particle nature- light has particle nature because it emits electrons when it strikes on metal surface called Photoelectric effect.

mass of photon is zero.

Formation of light energy -when we provide heat to an object it is start to emit photons.

The number of emitting photons, depending on temperature of the object. 

Photon having a special property that they can never exist in stable form. They start to travel since their formation.

Intensity of light inversely proportional to square of source distance.

7 properties of light – 

reflection, diffraction ,refraction ,polarization, interference ,dispersion, scattering.

Visible light is made up of seven colors known as VIBGYOR.

V – Violet 

I – Indigo

B – blue

G – green 

Y – yellow 

O – orange 

R – red

Where red light has the longest wavelength while violet light has the shortest wavelength.


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    1. Mam sorry for late replying
      But i love your question and i appreciate and welcome every question that is born out of curiosity,
      Here is a some different object and the velocity of sound
      Air 330m/sec
      Gold 3200m/sec
      Iron 5900m/sec
      Lead 2200m/sec
      Rubber 1800m/sec

      So by these value you can assume that velocity of sound is differ in every material

      Liked by 1 person

    1. Firstly thank u for visiting and here is your answer.
      Yeah that’s true
      Sound is slower in air and faster in water because of the particles of water.
      Water particles are packed in more densely,
      So the sound waves energy is transported faster in water.
      I hope i overcome your confusion.

      Liked by 2 people

  1. Thank you so much and we’re glad that you like our work
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    1. Sorry for late replying, because we have some pending work and here is your answer
      Differaction – bending or turning of wave.
      Refraction – change in direction of beam passing from one medium to another.
      Interference – combination of two or more wave superimpose.

      Thank you for visiting penser 😊

      Liked by 1 person

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