Nursing Elites

1. What is the phenomenon by which light bends as it passes through a prism known as?

• A. Reflection
• B. Electrical conduction
• C. Diffraction
• D. Refraction

Correct answer: D

Rationale: Refraction is the phenomenon by which light bends as it passes through a prism or any other medium boundary. When light transitions from one medium to another, such as air to glass in the case of a prism, it changes speed and direction due to the change in the medium's refractive index. This change in speed causes the light to bend. Reflection, on the other hand, is the bouncing back of light when it hits a surface. Diffraction refers to the bending of light around obstacles or through narrow openings. Electrical conduction involves the movement of electrically charged particles through a conductor, which is unrelated to the bending of light.

2. When a fluid encounters a bluff body (e.g., a car), the flow can separate behind the object, creating a region of low pressure. This phenomenon is known as:

• A. Cavitation
• B. Boundary layer separation
• C. Bernoulli effect per se
• D. Drag crisis

Correct answer: B

Rationale: The correct answer is B: Boundary layer separation. Boundary layer separation occurs when the flow of fluid detaches from the surface of a bluff body, leading to a low-pressure region behind the object. This separation creates a wake region with reduced pressure. Choice A, Cavitation, refers to the formation of vapor bubbles in a fluid and is not relevant in this context. Choice C, Bernoulli effect per se, does not specifically describe the phenomenon of flow separation behind a bluff body. Choice D, Drag crisis, is not the term used to describe the creation of a low-pressure region due to flow separation.

3. A spring has a spring constant of 20 N/m. How much force is needed to compress the spring from 40 cm to 30 cm?

• A. 200 N
• B. 80 N
• C. 5 N
• D. 2 N

Correct answer: D

Rationale: The change in length of the spring is 40 cm - 30 cm = 10 cm = 0.10 m. The force required to compress or stretch a spring is given by Hooke's Law: F = k × x, where F is the force, k is the spring constant (20 N/m in this case), and x is the change in length (0.10 m). Substituting the values into the formula: F = 20 N/m × 0.10 m = 2 N. Therefore, the correct answer is 2 N. Choice A (200 N) is incorrect because it miscalculates the force. Choice B (80 N) is incorrect as it does not apply Hooke's Law correctly. Choice C (5 N) is incorrect as it underestimates the force required.

4. Jon walks all the way around a rectangular park that is 1 km × 2 km. Which statement is true about Jon’s walk?

• A. The displacement of his walk is 3 kilometers, and the distance traveled is 0 kilometers.
• B. The displacement of his walk is 0 kilometers, and the distance traveled is 16 kilometers.
• C. The displacement of his walk is 6 kilometers, and the distance traveled is 0 kilometers.
• D. The displacement of his walk is 0 kilometers, and the distance traveled is 6 kilometers.

Correct answer: D

Rationale: Jon walks all the way around a rectangular park that is 1 km × 2 km, which means he walks a total distance of 6 kilometers (1 km + 2 km + 1 km + 2 km = 6 km). However, the displacement of his walk is 0 kilometers because he starts and ends at the same point after completing the rectangular path around the park. Displacement refers to the change in position from the starting point to the ending point, regardless of the actual distance traveled. Choice A is incorrect because the total distance traveled by Jon is 6 kilometers, not 0 kilometers. Choice B is incorrect as the displacement is not 0 kilometers, and the distance traveled is 6 kilometers, not 16 kilometers. Choice C is incorrect because the displacement is 0 kilometers, and the distance traveled is 6 kilometers, not 0 kilometers.

5. In open-channel flow, a critical property is the free surface, which refers to the:

• A. Interface between the liquid and the container walls
• B. Interface between the liquid and a surrounding gas
• C. Bottom of the channel
• D. Region of highest velocity within the liquid

Correct answer: B

Rationale: The free surface in open-channel flow refers to the interface between the liquid and the surrounding gas, typically the atmosphere. This interface is critical as it determines the boundary between the liquid flow and the open environment. Option A is incorrect as it refers to the liquid-container wall interface, not the free surface. Option C is incorrect because it represents the bottom of the channel, not the free surface. Option D is incorrect as it describes the region of highest velocity within the liquid, not the free surface. Therefore, the correct choice is B.

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