Nursing Elites

1. A 780-watt refrigerator is powered by a 120-volt power source. What is the current being drawn?

• A. 660 amperes
• B. 150 amperes
• C. 6.5 amperes
• D. 0.15 amperes

Correct answer: C

Rationale: To calculate the current being drawn by the refrigerator, you can use the formula: Current (I) = Power (P) / Voltage (V). Given that the power of the refrigerator is 780 watts and the voltage is 120 volts, you can plug these values into the formula to find the current: I = 780 watts / 120 volts = 6.5 amperes. Therefore, the current being drawn by the 780-watt refrigerator is 6.5 amperes. Choice A, 660 amperes, is incorrect as it is significantly higher than the correct answer. Choice B, 150 amperes, is also incorrect and too high. Choice D, 0.15 amperes, is incorrect as it is too low. The correct answer is 6.5 amperes.

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. In a static fluid, pressure (P) at a depth (h) is governed by the hydrostatic equation:

• A. P = ρgh
• B. P = γh
• C. P = μgh
• D. P = bh

Correct answer: A

Rationale: The correct formula for the pressure at a certain depth in a fluid according to the hydrostatic equation is P = ρgh. Here, ρ represents the fluid's density, g is the gravitational acceleration, and h is the depth. This formula shows that pressure increases linearly with the density of the fluid, the acceleration due to gravity, and the depth. Choices B, C, and D are incorrect because they do not accurately represent the relationship between pressure, density, gravitational acceleration, and depth in a static fluid.

4. A constant force is exerted on a stationary object. In this scenario, work is:

• A. Performed
• B. Not performed
• C. Partially performed
• D. Inconclusive without further information

Correct answer: B

Rationale: Work is only done when a force causes displacement. Since the object is stationary, no displacement occurs, and therefore, no work is performed. Choice A is incorrect because work requires both force and displacement. Choice C is incorrect as there is no partial work - work is either done or not done. Choice D is incorrect as the scenario provided is clear - the object is stationary, so no work is being performed.

5. Archimedes' principle explains the ability to control buoyancy, allowing:

• A. Objects to sink regardless of density differences.
• B. Airplanes to generate lift for flight.
• C. Submarines to adjust their buoyancy for submergence and resurfacing.
• D. Helium balloons to overcome gravity and float.

Correct answer: C

Rationale: Archimedes' principle states that the upward buoyant force acting on an object submerged in a fluid is equal to the weight of the fluid displaced by the object. Submarines control their buoyancy by adjusting the volume of water they displace, which allows them to submerge and resurface. Choice C is correct because it directly relates to the principle of buoyancy and how submarines utilize it. Choices A, B, and D are incorrect because they do not accurately reflect the application of Archimedes' principle in controlling buoyancy for submergence and resurfacing.

Similar Questions