
Question 1
Correct

Regarding metal wires, which of the following is the most important determinant of their resistance?
Your Answer: Resistivity
Explanation:Electrical resistivity is a measure of a material’s property to oppose the flow of electric current. This is expressed in Ohmmeters (Î©‹…m). The symbol of resistivity is usually the Greek letter Ï� (rho). A high resistivity means that a material does not conduct electric charge well.
Electrical resistivity is defined as the relation between the electric field inside a material, and the electric current through it as a consequence:
Ï� = E/J
in which Ï� is the resistivity of the material (Î©‹…m),
E is the magnitude of the electrical field in the material (V/m),
J is the magnitude of the electric current density in the material (A/m2)If the electric field (E) through a material is very large and the flow of current (J) is very small, it means that the material has a high resistivity.

This question is part of the following fields:
 Basic Physics


Question 2
Correct

Anaesthetic gas concentrations can be measured using a refractometer. The main principal which allows it to be used for this purpose is which of the following?
Your Answer: Refraction
Explanation:Refractometers measure the degree to which the light changes direction, called the angle of refraction. A refractometer takes the refraction angles and correlates them to refractive index (nD) values that have been established. Using these values, you can determine the concentrations of solutions.

This question is part of the following fields:
 Basic Physics


Question 3
Correct

The halfempty cylinder weighs 4.44 kg. The tare weight of a nitrous oxide cylinder is 4 kg. The molecular weight of nitrous oxide is 44gm. Based on the data, how many litres of nitrous oxide remains in the cylinder for use?
Your Answer: 224 litres
Explanation:The Tare weight of a cylinder is the weight when it is empty. So,
Weight of cylinder – tare weight = weight of remaining N2O (g).
4.44 kg – 4 kg = 0.44 kg
Here,
0.44 kg of nitrous oxide remains in the cylinderSince the molecular weight of nitrous oxide is 44 g and one mole of an ideal gas will occupy a volume of 22.4 litres at STP
Therefore amount left in the cylinder is several (gN2O/44) x 22.4 litres of N2O.(440/44) x 22.4 = 224 litres.

This question is part of the following fields:
 Basic Physics


Question 4
Correct

Many of the processes we deal with in anaesthesia are exponential. What is the underlying mathematical principle of an exponential process?
Your Answer: The rate of change of x is dependent on the magnitude of x
Explanation:The magnitude of x determines the rate of change of x. Firstorder drug kinetics is a good example. Most drugs’ plasma levels are controlled by an exponential process. The rate of change in drug metabolism is proportional to the current plasma concentration (socalled nonlinear kinetics).
A tearaway function is just one type of exponential relationship (y = ex), in which e is Euler’s number, x is the power, and e is the base. Natural logarithms rely on Euler’s number.
Euler’s number is a mathematical constant, not a mathematical principle. It’s referred to as an irrational number. This is a number that cannot be expressed as a simple fraction or a ratio.
A line or curve that acts as the limit of another line or curve is known as an asymptote. A washout exponential curve, for example, where the value y represents the plasma concentration of a drug in a single compartment model against time on the x axis. This descending curve approaches but never touches the x axis. This curve is asymptotic to the x axis, which is the curve’s asymptote. An asymptote isn’t just a characteristic of exponential curves.

This question is part of the following fields:
 Basic Physics


Question 5
Correct

The whole water content of the body is calculated by multiplying body mass with 0.6. This water is diffused into distinct compartments. Which fluid compartment can be measured indirectly?
Your Answer: Intracellular volume
Explanation:The total body water content of a 70kg man is (70 Ã— 0.6) = 42 litres. For a woman, the calculation is (70 Ã— 0.55) = 38.5 litres.
For a man, it is subdivided into:
Extracellular fluid (ECF) = 14L (1/3)
Intracellular fluid (ICF) = 28L (2/3).The ECF volume is further divided into:
Interstitial fluid = 10.5 litres
Plasma = 3 litres
Transcellular fluid (CSF/synovial fluid) = 0.5 litres.Directly measured fluid compartments:
Heavy water (deuterium) can be used to measure total body water content, which is freely distributed.
Albumin labelled with a radioactive isotope or using a dye called Evans blue can be used to measure Plasma volume . They do not diffuse into red blood cells.
Radiolabelled (Cr51) red blood cells can be used to measure total erythrocyte volume.
Inulin as the tracer can be used to measure ECF volume as it circulate freely in the interstitial and plasma volumes.Indirectly measured fluid compartments:
Total blood volume can be calculated with the level of haematocrit and the volume of total circulating red blood cells.
ICF volume can be calculated by subtracting ECF volume from total blood volume. 
This question is part of the following fields:
 Basic Physics


Question 6
Incorrect

With regards to this state of matter which has a volume but no definite shape, particles are not tightly packed together. These are incompressible although there is free movement within the volume. This statement best describes which one of the following states of matter?
Your Answer:
Correct Answer: Liquid
Explanation:The solid state of matter has a definite volume and shape and particles are packed closely together and are incompressible. Within this tight lattice, there is enough thermal energy to produce vibration of particles.
Liquids however have a volume but no definite shape. These particles are less tightly packed together. Although there is free movement within the volume, they are incompressible.
Gases, however, have no finite shape or volume and particles are free to move rapidly in a state of random motion. They are compressible and are completely shaped by the space in which they are held. Vapours exist as a gas phase in equilibrium with identical liquid or solid matter below its boiling point.
The most prevalent state of matter in the universe is plasma which is formed by heating atoms to very high temperatures to form ions.

This question is part of the following fields:
 Basic Physics


Question 7
Incorrect

Fixed performance devices like high air flow oxygen enrichment (HAFOE) masks have large volumes of air entrained into a flow of 100% oxygen. The term that best describes the physics behind air entrainment is?
Your Answer:
Correct Answer: Bernoulli's principle
Explanation:Bernoulli’s principle states that as the speed of a moving fluid increases, there is a simultaneously decrease in static pressure or a decrease in the fluid’s potential energy.
This is seen in the simultaneous increase in speed and kinetic energy and fall in pressure that causes entrainment of large volumes of air into a flow of 100% oxygen in the nozzle of HAFOE masks.The reduction in fluid pressure that happens when a fluid flows through a constriction in a tube is the Venturi effect.
When a flow of gas or liquid attaches itself to a nearby surface and remains attached even when the surface curves away from the initial direction of flow, this is the Coanda effect.
The branch of engineering and technology that is concerned with the building of devices that use the flow and pressure of a fluid for functions usually performed by electronic devices is Fluidics . Fluidic logic is used to power some ventilators.
The branch of engineering that utilises pressurised gases is Pneumatics.

This question is part of the following fields:
 Basic Physics


Question 8
Incorrect

What makes the ultrasound nebulizer efficient?
Your Answer:
Correct Answer: Reduction in gas flow resistance
Explanation:Smallest drops reach not only the upper but also the lower respiratory tracks. As a result, the ultrasonic nebulizer is most efficient for the therapy of pulmonary diseases and stands out as a robust and reliable support within the clinical setting.

This question is part of the following fields:
 Basic Physics


Question 9
Incorrect

Which of the following closely estimates the interstitial oncotic pressure acting on a pulmonary capillary?
Your Answer:
Correct Answer: 17 mmHg
Explanation:The starling forces operate to maintain a homeostatic flow across the pulmonary capillary bed.
The outward driving force comprises of the capillary hydrostatic pressure (13 mmHg), negative interstitial fluid pressure (zero to slightly negative), and interstitial colloid osmotic pressure (17 mmHg). The inward driving force is controlled by the plasma colloid osmotic pressure (25 mmHg).

This question is part of the following fields:
 Basic Physics


Question 10
Incorrect

General anaesthesia is administered to a patient in a hospital in Lhasa which is one of the highest cities in the world (at 11,975 feet). An Anaesthetic rotameter is normally calibrated at 20 C and 1 bar pressure and is known to be underread at altitude. The temperature of the theatre was 10 C. Which one of the following physical properties is responsible for the rotameter inaccuracy in these conditions?
Your Answer:
Correct Answer: Density of the gas
Explanation:Since the gas is less dense at higher altitudes, the density of a gas influences flows when passing through the orifice. Due to this reason, for a given flow rate, the bobbin will not be forced as far up the rotameter tube.
At higher altitudes, the volume of a fixed mass of gas increases, and therefore the molecules of gas are widely spaced resulting in a decrease in density with an increase in altitude.
Viscosity is simply termed as friction of gas. The viscosity of a gas is important only at low flow rates when the flow characteristic of the gas is laminar.
Charle’s law stated that the volume occupied by a fixed amount of gas is directly proportional to its absolute temperature (T) provided the pressure remains constant.
Boyle’s law for a fixed amount of gas at constant temperature, the pressure (P) and volume (V) are inversely proportional.

This question is part of the following fields:
 Basic Physics


Question 11
Incorrect

At a pH of 7, pure water has an hydrogen ion concentration of?
Your Answer:
Correct Answer: 100 nanomol/L
Explanation:pH is the negative log to the base 10 of hydrogen ion concentration:
So, what power produces the answer?
pH = – log10 [H+]
Making [H+] the subject:
[H+] = 10pH
Substituting, [H+] = 107
One nanomole = 1 x 109 or 0.000000001
107 = 1x 0.0000001 or 10 x 0.00000001 or 100 x 0.000000001
100 nanomole.

This question is part of the following fields:
 Basic Physics


Question 12
Incorrect

With regards to arterial oxygen content, which of the following contributes most from a quantitative perspective?
Your Answer:
Correct Answer: Haemoglobin concentration
Explanation:The amount of oxygen carried by 100 ml of blood is called the arterial oxygen content (CaO2)and is normally 1724 ml/dL and can be determined by this equation:
CaO2 = oxygen bound to haemoglobin + oxygen dissolved in plasma
CaO2 = (1.34 Ã— Hgb Ã— SaO2 Ã— 0.01) + (0.003 Ã— PaO2)
where:
1.34 = Huffner’s constant (D) – Huffner’s constant does not change and its magnitude relatively small.
Hgb is the haemoglobin level in g/dL and SaO2 is the percent oxyhaemoglobin saturation of arterial blood
PaO2 is (0.0225 = ml of O2 dissolved per 100 ml plasma per kPa, or 0.003 ml per mmHg).Quantitatively, the amount of oxygen dissolved in plasma is 0.3 mL/dL.
Henry’s law states that at constant temperature, the amount of gas dissolved at equilibrium in a given quantity of a liquid is proportional to the pressure of the gas in contact with the liquid.
Given a haemoglobin concentration of 15 g/dL and a SaO2 of 100% and a PaO2 of 13.3 kPa, the amount of oxygen bound to haemoglobin is 20.4 mL/100mL.
Cardiac output is an important determinant of oxygen delivery but does not influence the oxygen content of blood.

This question is part of the following fields:
 Basic Physics


Question 13
Incorrect

Which of the following derived SI units is correctly expressed as their base units?
Your Answer:
Correct Answer: Volt: m2.kg.s3.A1
Explanation:The following units are derived SI units of measurement.
Energy or work: kg.m2.s2
The Joule (J) is the energy transferred to an object when a force of one newton acts on that object in the direction of its motion through a distance of one meter or N.m.Power: kg.m2.s3
The Watt (W) = rate of transfer of energy or Joule per second J/s.Force: kg.m.s2
One Newton (N) which is the international unit of measure for force = 1 kilogram meter per second squared. 1 Newton of force is the force required to accelerate an object with a mass of 1 kilogram 1 meter per second per second.Volt: kg.m2.s3.A1
The volt (V) is defined as the potential difference across a conductor when a current of one ampere dissipates one watt of power or W/A.Pressure: kg.m1.s2
A pascal (Pa) is force per unit area or N/m2. 
This question is part of the following fields:
 Basic Physics


Question 14
Incorrect

A patient admitted to the hospital is on oxygen via a venturi mask. The air entrainment ratio is 1:9 i.e. 1 litre of 100% oxygen from the source entrains 9 litres of air from the atmosphere). The flow rate of 100% oxygen is 6L/minute. Based on the given data which of the following value approximates the oxygen concentration delivered to the patient?
Your Answer:
Correct Answer: 28%
Explanation:The formula for calculating air: oxygen entrainment ratio is given as :
100% ˆ’ FiO2 = air/oxygen entrainment ratio
Since FiO2 ˆ’ 21% and the entrainment ratio is already known. Substituting the values in the equation: x = FiO2.100 ˆ’ x = 9
x ˆ’ 21
100 ˆ’ x = 9(x ˆ’ 21)
100 ˆ’ x = 9x ˆ’ 189
10x = 289
x = 289/10
x = 28.9%. 
This question is part of the following fields:
 Basic Physics


Question 15
Incorrect

Very small SI units are easily expressed using mathematical prefixes. One femtolitre is equal to which of the following volumes?
Your Answer:
Correct Answer: 0.000, 000, 000, 000, 001 L
Explanation:Small measurement units are denoted by the following SI mathematical prefixes:
1 deci = 0.1
1 milli = 0.001
1 micro = 0.000001
1 nano = 0.000000001
1 pico = 0.000000000001
1 femto = 0.000000000000001 (used to measure red blood cell volume)
1 atto = 0.000000000000000001. 
This question is part of the following fields:
 Basic Physics


Question 16
Incorrect

Suppose the afterload and myocardial contractility remain unchanged, which of the following factors in the pressurevolume loop indicates an increase in the preload of the left ventricle?
Your Answer:
Correct Answer: Increased enddiastolic volume
Explanation:If the afterload and myocardiac contractility remains unchanged, an increase in the preload can be attributed to an increase in enddiastolic volume.
Preload can be defined as the initial stretching of the cardiac myocytes prior to contraction. Preload, therefore, is related to muscle sarcomere length. Because sarcomere length cannot be determined in the intact heart, other indices of preload are used such as ventricular enddiastolic volume or pressure. When venous return to the heart is increased, the enddiastolic pressure and volume of the ventricles are increased, which stretches the sarcomeres, thereby increasing their preload.

This question is part of the following fields:
 Basic Physics


Question 17
Incorrect

Which of the following statements is true regarding oxygen?
Your Answer:
Correct Answer: Forms molecules containing either two or three atoms
Explanation:Oxygen is formed by a molecule of oxygen and two molecules of hydrogen with a molecular formula of H2O
The critical temperature is defined as a temperature above which the substance cannot be liquefied, no matter how much pressure is applied.
Water has a critical temperature of 118.6oC. So, it cannot be liquified at room temperature.Medical oxygen cylinder is stored in a cylinder with a white shoulder and black body. Meanwhile, medial air is stored in cylinders with a white and black shoulder and a French grey body.
The partial pressure of air at a high altitude is less but the relative concentration remains constant.

This question is part of the following fields:
 Basic Physics


Question 18
Incorrect

Regarding gas laws, which one best explains the ability of a Bourdon gauge to measure temperature?
Your Answer:
Correct Answer: Charles's law
Explanation:Charles’ Law states that there is a direct correlation between temperature and volume, where pressure and amount gas are constant. As temperature increases, volume also increases.
Boyle’s Law states that Pressure is inversely proportional to volume, assuming that temperature and amount of gas are constant. As volume increases, pressure decreases. In Dalton’s law of partial pressure, the total pressure exerted by a mixture of gases is equal to the sum of the partial pressure of the gases in mixture.
According to Henry’s Law for concentration of dissolved gases, at a constant temperature, the amount of a given gas that dissolves in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid. An equivalent way of stating the law is that the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas above the liquid.
GayLussac’s Law states that the pressure of a given mass of gas varies directly with the absolute temperature of the gas, when the volume is kept constant. This law is very similar to Charles’ Law, with the only difference being the type of container. Whereas the container in a Charles’ Law experiment is flexible, it is rigid in a GayLussac’s Law experiment.

This question is part of the following fields:
 Basic Physics


Question 19
Incorrect

Which of the following is the smallest value of pressure?
Your Answer:
Correct Answer: 14.69 psi
Explanation:The SI unit of pressure is the pascal (Pa) and it is equal to one newton (N) per square meter (m2) or N/m2.
1 atmosphere (atm) is the equivalent of:
101325 Pa760 mmHg
1.01325 bar
1033.23 cmH2O.
14.69 pounds per square inch (psi)
1013.25 millibar (mbar) or hectopascals (hPa), and14.69 psi is equal to one atmosphere. The other values are equal to two atmospheres of pressure.

This question is part of the following fields:
 Basic Physics


Question 20
Incorrect

Very large SI units are easily expressed using mathematical prefixes. One terabyte is equal to which of the following numbers?
Your Answer:
Correct Answer: 1,000,000,000,000 bytes
Explanation:To denote large measured units, the following SI mathematical prefixes are used:
1 deca = 10 bytes (101)
1 hecto (h) = 100 bytes
1 kilo (k)= 1,000 bytes
1 mega (M) = 1,000,000 bytes
1 giga (G) = 1,000,000,000 bytes
1 Tera (T) = 1,000,000,000,000 bytes
1 Peta (P) = 1,000,000,000,000,000 bytes. 
This question is part of the following fields:
 Basic Physics

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