Nursing Elites

1. In fluid dynamics, the continuity equation, a fundamental principle, expresses the conservation of:

• A. Momentum
• B. Mass
• C. Energy
• D. Angular momentum

Correct answer: B

Rationale: The continuity equation in fluid dynamics is a statement of the conservation of mass, making choice B the correct answer. It states that the mass entering a system must equal the mass leaving the system, assuming no mass is created or destroyed within the system. Conservation of momentum (choice A) is related to Newton's laws of motion and is not directly expressed by the continuity equation. Conservation of energy (choice C) involves different principles like the first law of thermodynamics and is not the focus of the continuity equation. Angular momentum (choice D) is also a different concept related to rotational motion and not described by the continuity equation.

2. In a scenario where a transverse wave transports energy from north to south, in what direction do the particles in the medium move?

• A. Only north to south
• B. Both northward and southward
• C. Only east to west
• D. Both eastward and westward

Correct answer: B

Rationale: In a transverse wave, particles of the medium move perpendicular to the direction of energy transport. When the wave transports energy from north to south, the particles in the medium oscillate up and down, causing them to move both northward and southward. Choice A is incorrect because the particles move in both directions, not only from north to south. Choices C and D are incorrect as they mention directions that are not relevant to the scenario described in the question.

3. When a gas is compressed isothermally, we can say that:

• A. The gas performs work on the surroundings, and its internal energy increases.
• B. The gas performs work on the surroundings, and its internal energy decreases.
• C. The surroundings perform work on the gas, and its internal energy increases.
• D. The surroundings perform work on the gas, and its internal energy decreases.

Correct answer: D

Rationale: When a gas is compressed isothermally, the surroundings perform work on the gas. In this process, since the temperature remains constant (isothermal), the internal energy of the gas does not change. Therefore, the correct answer is that the surroundings perform work on the gas, and its internal energy decreases. Choices A, B, and C are incorrect because they incorrectly describe the direction of work and the change in internal energy during an isothermal compression.

4. The specific heat capacity of tin is 217 J/(g°C). Which of these materials would require about twice as much heat as tin to increase the temperature of a sample by 1°C?

• A. Copper [0.3844 J/(g°C)]
• B. Iron [0.449 J/(g°C)]
• C. Gold [0.1291 J/(g°C)]
• D. Aluminum [0.904 J/(g°C)]

Correct answer: D

Rationale: The correct answer is D: Aluminum. The specific heat capacity of aluminum is 0.904 J/(g°C), which is approximately 4 times that of tin. For a material to require about twice as much heat as tin to increase the temperature by 1°C, it should have a specific heat capacity roughly double that of tin. Therefore, aluminum fits this criterion better than the other options. Gold has a much lower specific heat capacity than tin, so it would require less, not more, heat to increase the temperature by 1°C. Copper and Iron also have specific heat capacities lower than tin, making them incorrect choices for requiring twice as much heat as tin.

5. A concave mirror with a focal length of 2 cm forms a real image of an object at an image distance of 6 cm. What is the object's distance from the mirror?

• A. 3 cm
• B. 6 cm
• C. 12 cm
• D. 30 cm

Correct answer: B

Rationale: The mirror formula, 1/f = 1/do + 1/di, can be used to solve for the object distance. Given that the focal length (f) is 2 cm and the image distance (di) is 6 cm, we can substitute these values into the formula to find the object distance. Plugging in f = 2 cm and di = 6 cm into the formula gives us 1/2 = 1/do + 1/6. Solving for do, we get do = 6 cm. Therefore, the object's distance from the mirror is 6 cm. Choice A (3 cm), Choice C (12 cm), and Choice D (30 cm) are incorrect distances as the correct object distance is determined to be 6 cm.

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