Principles of Instrumentation Flashcards
What is a wave ?
a regular repeating disturbance that transfers energy through a medium such as air or water.
What is diffraction
is the bending, spreading or change in direction of waves when they encounter an obstacle or aperture.
Maximum spread or diffraction occurs when
when the size of the aperture is similar to the wavelength of the wave
Velocity or Speed
The rate at which the wave propagates through the medium,
v = f λ. (frequency by wavelength)
Velocity at which sound travels through air at rtp
Sound is diffracted a lot, especially the lower frequencies which have a larger
wavelengths (50 Hz).
so lower frequency: larger wavelength: diffracts a lot
330 m/s
High frequency waves tend to have _______ (small/large) wavelengths and diffracts ________ (more/less)
to have small wavelengths and diffracts less
Mechanical vs Electromagnetic waves
mechanical e.g sound require a medium (such as air, water, or a solid) to travel through.
Em e.g light do not require a medium and can travel through a vacuum.
What are Electromagnetic Waves?
and what can it be used for
used to generate electricity and magnets.
James Maxwell showed that oscillating electric charges generate electromagnetic waves with both electric and magnetic field perpendicular to each other and the direction of travel. They move through space at about c=3×10 8 m/s.
In all other media, light
and other electromagnetic radiation travel at a slightly modified speed.
Velocity or Speed of light
c=3×10 8 m/s
electromagnetic waves travels at this same speed.
Types of waves in the Electromagnetic spectrum
Raging Martians Invaded Venus Using X-ray Guns.
Visible light is a small subset.
Radio Waves
Microwaves
Infrared (IR)
Visible Light
Ultraviolet (UV)
X-rays
Gamma Rays
longest wavelength to shortest
What is the wavelength of the Visible spectrum of light within the electromagnetic spectrum
wavelength of 350 - 750 nm
What are the properties of waves?
Waves Form Amazing Surf Parties
wavelength, frequency, amplitude, speed, period.
Wavelength
𝜆
The distance between two consecutive points in phase on the wave (e.g., crest to crest).
Frequency
𝑓
The number of wave cycles passing a point per second, measured in Hertz (Hz).
Amplitude
The height or intensity of the wave/disturbance.
Waves can have the same frequency but different amplitudes.
Range of human hearing in frequency.
20 - 20 000 Hz
What is Resonance?
phenomenon where an object vibrates with maximum amplitude when subjected to a periodic force at a frequency that matches its natural frequency.
Natural Frequency
Every object or system has a natural frequency at which it tends to vibrate when disturbed.
Why is resonance important in analytics?
Small probe can give a big signal or result.
You can measure precise frequencies and amplify the frequency.
