Light Flashcards

1
Q

Regarding pulse oximetry (true or false):

Beer’s Law governs absorption in substances of differing densities

A

True. The Bouguer-Lambert law also plays a role.

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2
Q

Regarding pulse oximetry (true or false):

Red light is absorbed at 910 nm

A

False. Red light is absorbed at 660 nm. Infrared light is absorbed at 910 nm.

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3
Q

Regarding pulse oximetry (true or false):

An isobestic point is found at 805 nm

A

True. This is the isobestic point for oxyhaemoglobin and deoxyhaemoglobin.

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4
Q

Regarding pulse oximetry (true or false):

Carboxyhaemoglobin may interfere with pulse oximetry

A

True. The pulse oximeter tends to read 97% saturation due to the absorption of light by carboxyhaemoglobin.

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5
Q

Regarding pulse oximetry (true or false):

Fetal haemoglobin may interfere with pulse oximetry

A

False. Fetal haemoglobin has no effect on pulse oximetry readings.

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6
Q

Regarding pulse oximetry (true or false):

Infrared gas analysis relies on similar principles to the pulse oximeter

A

True

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7
Q

Regarding the physical principles of light (true or false):

The angle at which light hits a surface is the angle of reflection

A

False. It is the angle of incidence.

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8
Q

Regarding the physical principles of light (true or false):

The angle of reflection equals the angle of incidence

A

True

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9
Q

Regarding the physical principles of light (true or false):

Fibreoptic bundles use total external reflection

A

False. Fibreoptic bundles rely upon total internal reflection.

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10
Q

Regarding the physical principles of light (true or false):

The speed of light is constant in all substances

A

False. The speed of light varies in different substances. Comparison of a particular substance to the speed of light in a vacuum leads to the index of refraction.

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11
Q

Regarding the physical principles of light (true or false):

Cladding glass has a lower index of refraction than core glass

A

True

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12
Q

Regarding the physical principles of light (true or false):

Refraction is demonstrated by objects appearing to bend when placed in water

A

True

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13
Q

Regarding infrared gas analysis, match the substance to the following statement:

Carbon Dioxide
Nitrous Oxide
Oxygen
Volatile Agents
Water

Maximally absorbs light at 4.26 μm

A

Carbon Dioxide

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14
Q

Regarding infrared gas analysis, match the substance to the following statement:

Carbon Dioxide
Nitrous Oxide
Oxygen
Volatile Agents
Water

Can cause falsely high CO2 readings

A

Water

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15
Q

Regarding infrared gas analysis, match the substance to the following statement:

Carbon Dioxide
Nitrous Oxide
Oxygen
Volatile Agents
Water

Is compensated for by modern analyzers

A

Nitrous Oxide

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16
Q

Regarding infrared gas analysis, match the substance to the following statement:

Carbon Dioxide
Nitrous Oxide
Oxygen
Volatile Agents
Water

Does not absorb infrared, due to its molecular structure

A

Oxygen

17
Q

Regarding infrared gas analysis, match the substance to the following statement:

Carbon Dioxide
Nitrous Oxide
Oxygen
Volatile Agents
Water

Absorbs infrared, due to its complex molecular structure

A

Volatile agents