Nursing Elites

1. What is the main difference between a reversible and irreversible process in thermodynamics?

• A. Reversible processes involve heat transfer, while irreversible processes do not.
• B. Reversible processes occur instantaneously, while irreversible processes take time.
• C. Reversible processes can be run in both directions with the same outcome, while irreversible processes cannot.
• D. Reversible processes violate the first law of thermodynamics.

Correct answer: C

Rationale: A reversible process is an idealized process that can be reversed without leaving any change in either the system or the surroundings. In contrast, irreversible processes cannot be reversed and often involve entropy production or dissipation. Choice A is incorrect because both reversible and irreversible processes can involve heat transfer. Choice B is incorrect as the speed of a process does not determine its reversibility. Choice D is incorrect because reversible processes do not violate the first law of thermodynamics; they comply with it by maintaining a balance between energy inputs and outputs. Therefore, the correct answer is C, as it accurately captures the main difference between reversible and irreversible processes in thermodynamics.

2. Given the four wires described here, which would you expect to have the greatest resistance?

• A. 1 km of American wire gauge 1; diameter 7.35 mm
• B. 1 km of American wire gauge 2; diameter 6.54 mm
• C. 1 km of American wire gauge 3; diameter 5.83 mm
• D. 1 km of American wire gauge 4; diameter 5.19 mm

Correct answer: D

Rationale: The wire with the greatest resistance is the one with the smallest diameter, as resistance is inversely proportional to cross-sectional area. Gauge 4 with a 5.19 mm diameter has the smallest diameter and, therefore, the greatest resistance. Choice A, B, and C have larger diameters compared to choice D, so they would have lower resistance values.

3. When calculating an object’s acceleration, what must you do?

• A. Divide the change in time by the velocity.
• B. Multiply the velocity by the time.
• C. Find the difference between the time and velocity.
• D. Divide the change in velocity by the change in time.

Correct answer: D

Rationale: When calculating an object's acceleration, you must divide the change in velocity by the change in time. Acceleration is defined as the rate of change of velocity with respect to time. By determining the ratio of the change in velocity to the change in time, you can ascertain how quickly the velocity of an object is changing, thereby finding its acceleration. Choice A is incorrect because acceleration is not calculated by dividing time by velocity. Choice B is incorrect as it describes multiplying velocity by time, which does not yield acceleration. Choice C is incorrect as finding the difference between time and velocity is not a method to calculate acceleration.

4. The operating principle of a metal detector relies on:

• A. The static presence of a permanent magnet
• B. The electromotive force induced by a changing magnetic field
• C. The high electrical conductivity of most metals
• D. The unique thermal signature of metallic objects

Correct answer: B

Rationale: The correct answer is B. Metal detectors work based on the principle of electromotive force induced by a changing magnetic field. When a metal object comes into contact with the detector's magnetic field, it disrupts the field, inducing a current in the metal that can be detected. This principle allows metal detectors to identify the presence of metallic objects without relying on the static presence of a permanent magnet, the high electrical conductivity of metals, or the thermal signature of the objects. Choice A is incorrect because metal detectors do not rely on a static magnet but on the interaction of metals with a changing magnetic field. Choice C is incorrect because while metals do have high electrical conductivity, this is not the principle underlying metal detectors. Choice D is incorrect because metal detectors do not operate based on the thermal signature of objects, but rather on their interaction with magnetic fields.

5. The specific heat capacity of water is about 2 J/g°C. How much energy would you need to heat 1 kilogram of water by 10°C?

• A. 420 J
• B. 4,200 J
• C. 42,000 J
• D. 420,000 J

Correct answer: C

Rationale: The formula to calculate the energy required to heat a substance is Q = m × c × ΔT, where m is the mass, c is the specific heat capacity, and ΔT is the change in temperature. Given that 1 kilogram of water is equal to 1,000 grams, the mass (m) is 1,000 g, the specific heat capacity (c) of water is 4.2 J/g°C (not 2 J/g°C), and the change in temperature (ΔT) is 10°C. Substituting these values into the formula: Q = 1,000 × 4.2 × 10 = 42,000 J. Therefore, the correct energy required to heat 1 kilogram of water by 10°C is 42,000 J. Choices A, B, and D are incorrect as they do not consider the correct specific heat capacity of water or the conversion of mass to grams.

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