Physics Flashcards
Beer’s Law
Beer’s law states that the absorption of radiation by a given thickness of a solution of a given concentration is the same as that of twice the thickness of a solution of half the concentration.
Bougner’s (or Lambert’s) Law
Bougner’s (or Lambert’s) law states that each layer of equal thickness absorbs an equal fraction of radiation which passes through it.
Boyle’s Law
Boyle’s law states that at constant temperature the volume of a given mass of gas varies inversely with absolute pressure.
Graham’s Law
Graham’s law states that the rate of diffusion of a gas is inversely proportional to the square root of molecular weight.
Raoult’s Law
Raoult’s law states that the depression or reduction of vapour pressure of a solvent is proportional to the molar concentration of the solute.
Eutectic Mixture
Eutectic mixture is formed by two compounds mixing to produce substance of a single set of physical characteristics. EMLA contains 2.5% lidocaine and 2.5% prilocaine in oil:water emulsion.
Force in base units
m.kg.s-2
Pressure in base units
m-1.kg.s-2
Energy or work in base units
m2.kg.s-2
Power/Watt in base units
m2.kg.s-3
Halothane
Halothane boils at 50°C and has a saturated vapour pressure (SVP) of 32.3 kPa. The SVP is almost identical to isoflurane, and this may allow them be delivered using the same vaporiser, for example, Oxford miniature vaporiser.
All volatile agents inhibit hypoxic pulmonary vasoconstriction and therefore increase shunting.
Halothane sensitises the myocardium to circulating catecholamines and this is one reason why surgeons usually ask the anaesthetist prior to infiltrating epinephrine (adrenaline) containing local anaesthetics.
The minimum alveolar concentration (MAC) of halothane is 0.7%.
Halothane causes less cerebral vasoconstriction than isoflurane, which explains why isoflurane is popular in neuroanaesthesia.
K from Celcius
K = C + 273.15
C from K
C = K - 273.15
What is the Seebeck Effect?
the principle that two different metals in contact generate a voltage, which is temperature dependent
What is a thermopile
Several Thermocouples in series
Tell me about Thermocouples
Found in most thermometers (except those in catheters);
Based on the Seebeck effect that two different metals in contact will generate a voltage which is temperature dependent.
Copper-Constantan is commonly used.
It generates a linear-relationship between Voltage and Temperature.
Tell me about Thermistors
A Thermistor is a type of resistor that has a resistance that changes with temperature.
It allows accurate temperature measurement to an order of 0.1 degrees C.
It is made of semiconductor beads using oxides such as chromium, cobalt, iron, manganese.
A negative temperature coefficient is normally present i.e. as Temperature increases, resistance decreases. However positive temperature coefficients exits.
It shows a non-linear relationship.
Cheap, small, suitable for catheters and oesophageal temp probes.
1 tesla is how many guass
10000
Fully saturated air at 20 degrees C contains how much water?
17g/m3
Fully saturated air at 37 degrees C contains how much water?
44g/m3
Breathing systems filters work on the principles of:
Interception - when a particle following a gas stream around one fibre collides with an adjacent fibre
Inertia - when a particle cannot follow a gas stream around the fibre so impacts against the fibre
Diffusion - when small particles which undergo Brownian motion increasing their probability of striking a fibre
Gravity - when large or heavy particles fall onto fibres as a result of gravity
Electrostatic - when charged air particles are attracted to oppositely charged fibres.
Full cylinder of Oxygen at 15 degrees C has a pressure of:
13700 kpa
Full cylinder of CO2 at 15 degrees C has a pressure of:
5000 kpa (723 psi)
Full cylinder of Entonox at 15 degrees C has a pressure of:
13700 kpa
Full cylinder of Nitrous Oxide at 15 degrees C has a pressure of:
4400 kpa
Full cylinder of Medical Air at 15 degrees C has a pressure of:
13700 kpa
Full cylinder of Cyclopropane at 15 degrees C has a pressure of:
436 kpa
What are the seven base units?
Metre
Second
Kg
Ampere
Kelvin
Candela
Mole
How many litres does a size E oxygen cylinder hold?
680L
How many litres does a size J oxygen cylinder hold?
6800L
Symptoms experienced by different level of currents:
1 mA - tingling pain
5 mA - pain
15 mA - tonic muscular contraction
50 mA - respiratory muscle paralysis
75 mA - ventricular fibrillation.
Force
In physics, a force is an influence that can cause an object to change its velocity, i.e., to accelerate, meaning a change in speed or direction
Mass x Acceleration