Nursing Elites

1. When a hot cup of coffee is placed on a cold table, heat transfer primarily occurs through which process?

• A. Radiation
• B. Conduction
• C. Convection within the coffee
• D. A combination of conduction and convection

Correct answer: B

Rationale: When a hot cup of coffee is placed on a cold table, heat transfer primarily occurs through conduction. Conduction is the process of heat transfer through direct contact between objects at different temperatures. In this scenario, the heat from the hot coffee cup is transferred to the cold table through direct contact, making conduction the primary mode of heat transfer. Choice A (Radiation) is incorrect because radiation is the transfer of heat through electromagnetic waves, which is not the primary mode of heat transfer in this scenario. Choice C (Convection within the coffee) is incorrect because convection is the transfer of heat through the movement of fluids, which is not the primary mode of heat transfer in this scenario. Choice D (A combination of conduction and convection) is incorrect because while convection may play a minor role due to air currents around the cup, the primary mode of heat transfer in this scenario is conduction.

2. An object has a constant velocity of 50 m/s and travels for 10 s. What is the acceleration of the object?

• A. 0 m/s²
• B. 5 m/s²
• C. 60 m/s²
• D. 500 m/s²

Correct answer: A

Rationale: The acceleration of an object is defined as the rate of change of its velocity. When an object has a constant velocity, it means there is no change in its speed or direction. In this case, the object maintains a constant velocity of 50 m/s for 10 seconds, which implies that there is no change in velocity. Therefore, the acceleration of the object is 0 m/s² as there is no acceleration or deceleration happening. Choices B, C, and D are incorrect because acceleration is the change in velocity over time, and in this scenario of constant velocity, the acceleration is 0 m/s².

3. An airplane travels 500 miles northeast and then, on the return trip, travels 500 miles southwest. Which of the following is true?

• A. The displacement of the plane is 1,000 miles, and the distance traveled is 0 miles.
• B. The displacement of the plane is 1,000 miles, and the distance traveled is 1,000 miles.
• C. The displacement of the plane is 0 miles, and the distance traveled is 0 miles.
• D. The displacement of the plane is 0 miles, and the distance traveled is 1,000 miles.

Correct answer: D

Rationale: The displacement of an object is the change in position from the starting point to the ending point, regardless of the path taken. In this case, the airplane returns to its original position after traveling 500 miles northeast and then 500 miles southwest. Therefore, the displacement is 0 miles. However, the distance traveled is the total path covered, which is 500 miles northeast plus 500 miles southwest, for a total of 1,000 miles. Choice A is incorrect because the displacement is not the sum of the distances traveled. Choice B is incorrect as it incorrectly states that both the displacement and the distance traveled are 1,000 miles. Choice C is incorrect as it states that both the displacement and the distance traveled are 0 miles, which is not the case.

4. Household alternating current typically has a frequency of 60 Hz. Which statement is true?

• A. The circuit is suitable for lighting 60-watt bulbs.
• B. Circuits in the home may carry a current of 60 amperes.
• C. The expected voltage drop is 60 volts per meter.
• D. Electrons complete a cycle 60 times per second.

Correct answer: D

Rationale: The correct answer is D. Electrons complete a cycle 60 times per second when the frequency of the current is 60 Hz. This frequency indicates that the current changes direction 60 times per second, causing the electrons to complete a full cycle back and forth through the circuit at the same rate. Choice A is incorrect because the power rating of a bulb (in watts) is not directly related to the frequency of the current. Choice B is incorrect as typical household circuits do not carry currents as high as 60 amperes. Choice C is incorrect as the expected voltage drop is not measured in volts per meter for household alternating current circuits.

5. The buoyant force, F_b, experienced by an object submerged in a fluid is given by:

• A. F_b = W, the object's weight
• B. F_b = W_d, the weight of the fluid displaced by the object
• C. F_b = ρ, the density of the fluid
• D. F_b = V, the object's volume

Correct answer: B

Rationale: The correct formula for the buoyant force experienced by an object submerged in a fluid is given by Archimedes' principle, which states that the buoyant force is equal to the weight of the fluid displaced by the object. This is represented by the formula F_b = W_d, where W_d is the weight of the fluid displaced by the object. This force acts in the opposite direction to gravity and is responsible for objects floating or sinking in fluids. Choice A is incorrect because the buoyant force is not equal to the object's weight. Choice C is incorrect because the density of the fluid is not directly related to the buoyant force. Choice D is incorrect because the object's volume is not the determining factor for the buoyant force.

Similar Questions