Nursing Elites

1. 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.

2. A closed system undergoes a cyclic process, returning to its initial state. What can be said about the net work done (Wnet) by the system over the entire cycle?

• A. Wnet is always positive.
• B. Wnet is always negative.
• C. Wnet can be positive, negative, or zero.
• D. Wnet is equal to the total heat transferred into the system (dQ ≠ 0 for a cycle).

Correct answer: C

Rationale: For a closed system undergoing a cyclic process and returning to its initial state, the net work done (Wnet) over the entire cycle can be positive, negative, or zero. This is because the work done is determined by the area enclosed by the cycle on a P-V diagram, and this area can be above, below, or intersecting the zero work axis, leading to positive, negative, or zero net work done. Choice A is incorrect because Wnet is not always positive; it depends on the specific path taken on the P-V diagram. Choice B is incorrect as Wnet is not always negative; it varies based on the enclosed area. Choice D is incorrect because Wnet is not necessarily equal to the total heat transferred into the system; it depends on the specifics of the cycle and is not a direct relationship.

3. When a small object floats on the surface of a liquid, the surface tension creates a:

• A. Buoyant force acting upwards
• B. Pressure difference causing sinking
• C. Drag force opposing motion
• D. Restoring force towards equilibrium

Correct answer: D

Rationale: Surface tension creates a restoring force that holds the object on the surface. The liquid's surface behaves like a stretched membrane, and when disturbed, it tends to return the object to its original position, creating a restoring force. The other choices are incorrect: A buoyant force acts on objects submerged in a fluid, not floating on the surface; pressure differences usually affect sinking objects, not floating ones; drag force is a resistance force that opposes motion, not related to surface tension.

4. Two objects attract each other with a gravitational force of 12 units. If you double the mass of both objects, what is the new force of attraction between them?

• A. 3 units
• B. 6 units
• C. 24 units
• D. 48 units

Correct answer: C

Rationale: The gravitational force between two objects is directly proportional to the product of their masses. When you double the masses of both objects, the force of attraction between them increases by a factor of 2 x 2 = 4. Therefore, the new force of attraction between the two objects will be 12 units x 4 = 24 units. Choices A, B, and D are incorrect because doubling the mass results in a quadruple increase in force, not a linear one.

5. When calculating an object’s acceleration, what must you do?

• A. Divide the change in time by the velocity.
• B. Multiply the velocity by the time.
• C. Find the difference between the time and velocity.
• D. Divide the change in velocity by the change in time.

Correct answer: D

Rationale: When calculating an object's acceleration, you must divide the change in velocity by the change in time. Acceleration is defined as the rate of change of velocity with respect to time. By determining the ratio of the change in velocity to the change in time, you can ascertain how quickly the velocity of an object is changing, thereby finding its acceleration. Choice A is incorrect because acceleration is not calculated by dividing time by velocity. Choice B is incorrect as it describes multiplying velocity by time, which does not yield acceleration. Choice C is incorrect as finding the difference between time and velocity is not a method to calculate acceleration.

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