What do you mean by intensity and relationship with amplitude
Answers
Explanation:
the intensity is directly proportional to the power of the source and inversely proportional to its unit area, while the amplitude is simple the maximum displacement of a wave.
Answer:intensity vs. amplitude
The amplitude of a sound wave can be quantified in several ways, all of which are a measure of the maximum change in a quantity that occurs when the wave is propagating through some region of a medium.
Amplitudes associated with changes in kinematic quantities of the particles that make up the medium
The displacement amplitude is the maximum change in position.
The velocity amplitude is the maximum change in velocity.
The acceleration amplitude is the maximum change in acceleration.
Amplitudes associated with changes in bulk properties of arbitrarily small regions of the medium
The pressure amplitude is the maximum change in pressure (the maximum gauge pressure).
The density amplitude is the maximum change in density.
Measuring displacement might as well be impossible. For typical sound waves, the maximum displacement of the molecules in the air is only a hundred or a thousand times larger than the molecules themselves — and what technologies are there for tracking individual molecules anyway? The velocity and acceleration changes caused by a sound wave are equally hard to measure in the particles that make up the medium.
Density fluctuations are minuscule and short lived. The period of a sound wave is typically measured in milliseconds. There are some optical techniques that make it possible to image the intense compressions are rarefactions associated with shock waves in air, but these are not the kinds of sounds we deal with in our everyday lives.
Pressure fluctuations caused by sound waves are much easier to measure. Animals (including humans) have been doing it for several hundred million years with devices called ears. Humans have also been doing it electromechanically for about a hundred years with devices called microphones. All types of amplitudes are equally valid for describing sound waves mathematically, but pressure amplitudes are the one we humans have the closest connection to.
In any case, the results of such measurements are rarely ever reported. Instead, amplitude measurements are almost always used as the raw data in some computation. When done by an electronic circuit (like the circuits in a telephone that connect to a microphone) the resulting value is called intensity. When done by a neuronal circuit (like the circuits in your brain that connect to your ears) the resulting sensation is called loudness.
The intensity of a sound wave is a combination of its rate and density of energy transfer. It is an objective quantity associated with a wave. Loudness is a perceptual response to the physical property of intensity. It is a subjective quality associated with a wave and is a bit more complex. As a general rule the larger the amplitude, the greater the intensity, the louder the sound. Sound waves with large amplitudes are said to be "loud". Sound waves with small amplitudes are said to be "quiet" or "soft". The word "low" is sometimes also used to mean quiet, but this should be avoided. Use "low" to describe sounds that are low in frequency. Loudness will be dealt with at the end of this section, after the term level and its unit the decibel have been defined.
By definition, the intensity (I) of any wave is the time-averaged power (⟨P⟩) it transfers per area (A) through some region of space. The traditional way to indicate the time-averaged value of a varying quantity is to enclose it in angle brackets (⟨⟩). These look similar to the greater than and less than symbols but they are taller and less pointy. That gives us an equation that looks like this…
I = ⟨P⟩ /A
The SI unit of power is the watt, the SI unit of area is the square meter, so the SI unit of intensity is the watt per square meter — a unit that has no special name.