Nursing Elites

1. Entropy (S) is a thermodynamic property related to the system's disorder. According to the second law of thermodynamics, in a spontaneous process:

• A. The total entropy of the system and surroundings increases.
• B. The total entropy of the system and surroundings decreases.
• C. The total entropy of the system remains constant.
• D. The total entropy of the surroundings increases, while the system's entropy decreases.

Correct answer: A

Rationale: The second law of thermodynamics asserts that the entropy of an isolated system (or the combined system and surroundings) will always increase in a spontaneous process, reflecting an increase in disorder. Therefore, the correct answer is that the total entropy of the system and surroundings increases. Choice B is incorrect because entropy always tends to increase in a spontaneous process, as dictated by the second law of thermodynamics. Choice C is incorrect as entropy typically increases in natural processes. Choice D is incorrect because the second law of thermodynamics states that the total entropy of the system and surroundings always increases in a spontaneous process.

2. Fluid dynamics is a subfield of fluid mechanics concerned with:

• A. Equilibrium properties of fluids at rest (Fluid Statics)
• B. The motion and behavior of fluids under various conditions
• C. Phase transitions of fluids between liquid, gas, and solid states
• D. Engineering applications of fluids (related but broader than fluid dynamics)

Correct answer: B

Rationale: Fluid dynamics is the study of fluids in motion and their behavior under different conditions, including how they flow, mix, and interact with their surroundings. It focuses on the dynamic aspects of fluids rather than their static properties when at rest, which is the realm of fluid statics. Phase transitions of fluids between liquid, gas, and solid states are more related to thermodynamics than fluid dynamics. While engineering applications involve fluid dynamics, the field itself is more specialized in studying the movement and behavior of fluids.

3. The frequency of an alternating current (AC) refers to the number of times it changes direction per unit time. This is measured in:

• A. Hertz
• B. Amperes
• C. Volts
• D. Ohms

Correct answer: A

Rationale: The frequency of an alternating current (AC) is measured in Hertz (Hz), which denotes the number of times the current changes direction per unit time. Hertz is the unit for frequency, while amperes measure current, volts measure voltage, and ohms measure resistance. Therefore, the correct answer is Hertz (Hz). Choices B, C, and D are incorrect because amperes measure current intensity, volts measure voltage potential, and ohms measure resistance, not the frequency of an alternating current.

4. What is the purpose of a switch in a circuit?

• A. To reverse the direction of alternating current
• B. To increase the voltage of the battery or cell
• C. To increase the resistance of wires in the circuit
• D. To allow the circuit to open and close

Correct answer: D

Rationale: The purpose of a switch in a circuit is to allow the circuit to open and close. When the switch is turned on, it provides a complete path for the current to flow through the circuit. When the switch is turned off, it breaks the circuit, stopping the flow of current. This function of opening and closing the circuit using a switch is essential for controlling the flow of electricity in various electrical devices and systems. Choices A, B, and C are incorrect because a switch does not reverse the direction of current, increase voltage, or increase resistance in a circuit; its primary function is to open and close the circuit.

5. The drag force (F_d) experienced by an object moving through a fluid depends on:

• A. Object's shape and size only
• B. Fluid properties and object velocity
• C. Depth of submersion only
• D. Buoyant force acting on the object

Correct answer: B

Rationale: The drag force experienced by an object moving through a fluid depends on multiple factors, including the object's shape, size, velocity, and the fluid's properties such as viscosity and density. Choices A, C, and D are incorrect because drag force is not solely determined by the object's shape and size, depth of submersion, or buoyant force acting on the object. The primary factors affecting drag force are the fluid properties and the object's velocity. Therefore, the correct answer is B.

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