Nursing Elites

1. When a junked car is compacted, which statement is true?

• A. Its mass increases.
• B. Its mass decreases.
• C. Its density increases.
• D. Its density decreases.

Correct answer: C

Rationale: When a junked car is compacted, its volume decreases while its mass remains the same. As a result, the car's density increases because density is mass divided by volume. Choice A is incorrect because the mass of the car remains the same. Choice B is incorrect because the mass does not decrease. Choice D is incorrect because the density increases as the volume decreases, not decreases.

2. A 3-volt flashlight uses a bulb with 60-ohm resistance. What current flows through the flashlight?

• A. o.05 amp
• B. o.5 amp
• C. 1.8 amp
• D. 18 amp

Correct answer: A

Rationale: : Using Ohm's Law, I = V / R: I = 3 / 60 = 0.05 amp. So, the correct current is 0.05 amp.

3. When a car is driven for a long time, the pressure of air in the tires increases. This is best explained by which of the following gas laws?

• A. Boyle's law
• B. Charles' law
• C. Gay-Lussac's law
• D. Dalton's law

Correct answer: C

Rationale: Gay-Lussac's law, also known as the law of pressure-temperature, states that the pressure of a gas is directly proportional to its absolute temperature when the volume is constant. As a car is driven for a long time, the tires heat up due to friction and increased air pressure inside the tires. This results in an increase in temperature, causing the pressure of the air inside the tires to increase according to Gay-Lussac's law. Choices A, B, and D are incorrect. Boyle's law relates pressure and volume, Charles' law relates volume and temperature, and Dalton's law deals with the partial pressures of gases in a mixture.

4. 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.

5. A Carnot cycle is a theoretical ideal heat engine operating between two heat reservoirs at different temperatures. Which of the following statements is NOT true about a Carnot cycle?

• A. The efficiency of a Carnot cycle is solely dependent on the absolute temperatures of the hot and cold reservoirs.
• B. It is a reversible cycle, meaning the process can be run in both directions with the same efficiency.
• C. It operates isothermally at the hot and cold reservoir temperatures.
• D. It is the most efficient heat engine operating between the same two reservoir temperatures.

Correct answer: C

Rationale: The statement that is NOT true is C. Although part of the Carnot cycle operates isothermally, not the entire cycle operates isothermally. The Carnot cycle consists of both isothermal and adiabatic processes. Choice A is incorrect because the efficiency of a Carnot cycle is indeed solely dependent on the absolute temperatures of the hot and cold reservoirs. Choice B is correct as a Carnot cycle is reversible, allowing the process to be run in both directions with the same efficiency. Choice D is also true as the Carnot cycle is the most efficient heat engine operating between the same two reservoir temperatures. Therefore, the correct answer is C.

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