Physics 6-others Flashcards
X-rays have what sort of frequency + wavelength?
high frequency
short wavelength
For fluroscopes, what is used which decreases the intensity required from x-rays?
image intensifier
how does ultrasound imaging work?
measures the it takes for an ultrasound to be reflected back from partial reflection
What can ultrasounds be used for with kidneys?
used to breakdown kidney stones
What can ultrasounds be used for with fetuses?
Ultrawaves reflect back from the fluid in womb + skin of the fetus and echoes reflected back are transmitted into an image
What can ultrasounds be used for with blood?
Measure blood flow + see for any blockages
what are the dangers of xrays and CT scans
They are both ionising
What can be used to check % oxygen in the blood
Pulse Oximeters
How do Pulse Oximeters work?
Patients with high oxyhaemoglobin levels will absorb the Infrared light meaning not a lot passes through
Anaemic patients have a low oxyhaemoglobin levels and dont absorb Infrared well
WIth PET scans, what is inserted into patients?
Positron emitting radioisotope
What happens when positrons and electrons colide?
how can this be used in medicine
they colide(annihalaiton) and create Gamma Waves
Tumour cells take up radio isotope more than normal cells
detection of gamma waves where radio tracer is found
The resting potential in a muscle cell is what?
Whats the mV?
P.D across the cell membrane at rest
-70mV
When SAN sends a pulse, what happens to the resting potential. whats this called?
Changes to +40mV
Action potential
P wave defines what?
QRS wave defines what?
T wave defines what?
Atria Contracting
Ventricles Contracting
Relaxation of Ventricles
Working out HR using ECG =
Frequency = 1/time period (peak-peak)
x60 = HR
Why are there no green stars?
Stars are only red/yellow/orange/blue
Green will contain high red + blue = white
Hot objects emit what?
What will they always emit more of?
radiation
Emit more of one frequency of radiation
The peak frequency of a hot object depends on what?
temperature
the higher it is, the higher the peak
Luminosity/brightness depends on what?
If a star is red what does this mean?
temperature
Cool star (low frequency)
what is red in terms of frequency / temperature
what is orange
what is blue
low
medium
high
Electrons with the lowest energy levels are found where?
near the nucleus
Absorption spectra, why do gaps formed when continuous light is passed through a gas?
Electrons in the gas absorb certain frequencies of light
forms dark lines
With emission spectra, why do bright lines form?
electrons fall from higher to lower levels and emit radiation of a particular frequency
Each element has its own what (spectra)
own line spectrum
