Flashcards
P3 Edexcel Further Additional Topic 2
Cards in this deck (25)
- 1Describe the relationship between the frequency of an x-ray and energy/ionisation of an x-ray.The higher the frequency of an x-ray the greater its energy/ability to ionise
- 2State the three main parts of an x-ray tube.1) An evacuated tube
2) A positive anode (metal target)
3) A negative cathode (metal filament)
- 3Explain the term thermionic emission.Thermionic emission is where electrons are released/boiled off from a heated filament
- 4Explain the need for a potential difference between the cathode and anode of an x-ray tube.The potential difference accelerates the electrons released through thermionic emission towards the metal target.
- 5State what is released when electrons collide with a metal target.X-rays can be produced when electrons collide with a metal target.
- 6Explain why the x-ray tube must be evacuated (a vacuum).So that the electrons do not collide with particles in the air. This would stop them reaching the anode/metal target.
- 7Explain why a beam of charged particles is equivalent to an electric current.This is because both produce a flow of charge.
- 8State the equation that relates current, I, number of particles per second, N and charge of each particles, qI = N x q
- 9State the equation that relates kinetic energy, KE, charge on an electron, e and accelerating potential difference, V.KE = e x V
OR
1/2 x m x v^2 = e x V - 10Define the term inverse square law.The value (such as intensity) is indirectly proportional to a square of the distance.
e.g. If distance doubles, intensity is reduced by 4 (2 squared).
If distance triples, intensity is reduced by 9 (3 squared).
- 11Describe the relationship between the thickness of a materials and its ability to absorb x-rays.The thicker a material the greater it's absorption of x-rays.
- 12Describe how x-rays are used in fluoroscopes.The patient stands between an X-ray source and a fluorescent screen and a large number of images are taken to form a short film/moving images.
- 13Justify the used of x-rays in medicine.The benefits outweigh the risks
Benefits: diagnosis and treatment, painless, avoids surgery/biopsy.
Risks: High doses of ionising radiation, possible mutation of cells, risk of cancer.
- 14Relate the ECG to the action of the heart.P: contraction of the atria (atrial de-polarisation).
QRS: contraction of the ventricles (ventricle de-polarisation).
T: Relaxation of the ventricles (ventricle re-polarisation)
- 15State the normal resting heartbeat.Normal resting heart beat is 60-80 bpm.
- 16Define the term action potential.An action potential is the change in the potential different across the cell membrane that causes the muscle to contract.
- 17State the heart problems that can be diagnosed using an ECG.Fast heartbeat (tachycardia), slow heartbeat (bradycardia) and irregular heartbeat (arrhythmia)
- 18State the equation that relates frequency, f and time period, T.f = 1 / T
- 19State the number of milliseconds in a secondThere are 1000 milliseconds in a second.
1 milliseconds = 0.001 seconds
- 20Describe how to convert beats per second (bps) to beats per minute (bpm)Multiply the beats per second by 60 to find the beats per minute.
- 21Describe the use of a pacemaker to regulate heart action.A pace maker amplifies or produces the action potential within the heart by sending an electrical impulse.
- 22State the uses of pulse oximetry.Pulse oximetry can be used to monitor the pulse the oxygen content of the blood.
- 23Explain the use of pulse oximetry.The device passes two beams of light (a red and an infra-red beam) through the patient to a sensor.
The difference in the absorbency of these two beams of light determines the amount of oxygen in the blood.
- 24State the type of light absorbed by oxyhaemoglobinMore infra-red light then red light is absorbed by oxyhaemoglobin.
- 25State the type of light absorbed by reduced haemoglobinMore red light then infra-red light is absorbed by reduced haemoglobin.
Information
- Description
- Recall information for P3
- Created by
- Mr M Liddle
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- Created by Mr M Liddle · May 5, 2016
- Copied by Mr M Liddle · May 15, 2016
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