The range of audible frequencies of a person with normal hearing
20-20,000Hz
1 of 33
Intensity
The power per unit instrumental area
2 of 33
Intensity Level
A logarithmic measure of sound intensity given by: IL = 10log(I x 1012)
3 of 33
The magnitude at which discomfort is experienced for a person with normal hearing
140dB
4 of 33
Effect on hearing due to short-term exposure to noise
Tinnitus
5 of 33
Effects on hearing due to long-term exposure to noise
Deafness due to damage to eardrum, permanent ringing in ears and selective frequency losses.
6 of 33
Ultrasound
Sound of a frequency above the upper limit of hearing of a human being.
7 of 33
How can ultrasound be produced
By applying an alternating voltage to a Piezo-electric crystal so that it 'tenses up' rapidly, causing vibrations in the air (an ultrasound wave).
8 of 33
Attenuation Coefficient
The extent to which a beam's intensity is reduced as it passes through a material.
9 of 33
Half-value thickness
The thickness a beam must pass through before its intensity is reduced to half of it's initial intensity.
10 of 33
Quality factor
Tells you how damaging radiation is compared to X-rays
11 of 33
The regions of the EM spectrum used for the lasers in pulse oximetry
Visible (red) and infrared
12 of 33
Differences in response to exposure to radiation between cancerous cells and normal cells
Cancerous cells are more easily killed. The rate of repair of cancerous cells is slower.
13 of 33
Light year
The distance light travels in a vacuum in one year
14 of 33
Luminosity
The power radiated by a star.
15 of 33
Apparent brightness
How bright a star appears from Earth.
16 of 33
Apparent magnitude
How large a star appears from Earth.
17 of 33
Absolute magnitude
The apparent brightness a star would have if placed 10 parsecs from Earth.
18 of 33
Wien's displacement law
Relates wavelength and surface temperature. The higher the temperature, the lower the wavelength at which most of the energy is radiated.
19 of 33
Main sequence star
Stars which produce enough energy through nuclear fusion to exactly counterbalance their weight.
20 of 33
Red Giants
Large, cool stars with a red appearance. Their luminosity is considerably greater than that of a main sequence star of the same temperature. They aren’t very dense having a central hot core surrounding by an enormous envelope of extremely tenuous gas
21 of 33
White Dwarfs
Small and faint. Form when a star collapses but its own gravity stabilises as a result of electron degeneracy pressure.
22 of 33
Cepheids
A type of variable star that has a period of luminosity, with a peak luminosity.
23 of 33
Binary Stars
A system where two stars orbit a common centre.
24 of 33
Electron degeneracy pressure
When the electrons of the star are forced into the same quantum states. This forces them to acquire large kinetic energies which can withstand the gravitational pressure of the star.
25 of 33
Parsec
A distance that corresponds to a parallax angle of 1 arcsecond.
26 of 33
Newton's model of the universe
The universe is infinite in extent, has no beginning and is static. It has been uniform and isotropic at all times.
27 of 33
The Homogeneity principle
The idea that on a large scale the universe looks uniform.
28 of 33
The Isotropy principle
If you look in different directions you see essentially the same thing. If you look far enough in one direction you will count the same number of galaxies as you would looking far enough in any other direction.
29 of 33
Cosmological principle
The universe has no edge and no centre for these areas would look different from the rest of the universe.
30 of 33
Chandrasekhar limit
The limit that dictates whether a star will become a white dwarf or supernova.
31 of 33
Oppenheimer-Volkoff limit
The limit at which the mass of a star is great enough for it to become a black hole.
32 of 33
Hubble's Law
All galaxies are moving away from us and their velocity of recession is proportional to their distance from us.
33 of 33
Other cards in this set
Card 2
Front
The power per unit instrumental area
Back
Intensity
Card 3
Front
A logarithmic measure of sound intensity given by: IL = 10log(I x 1012)
Comments
No comments have yet been made