Nursing Elites

1. Enthalpy (H) is a thermodynamic property defined as the sum of a system's internal energy (U) and the product of its pressure (P) and volume (V). The relationship between these is:

• A. H = U + PV
• B. H = U - PV
• C. H = U / PV
• D. H = PV / U

Correct answer: A

Rationale: Enthalpy (H) is defined as H = U + PV, where U represents internal energy, P is pressure, and V is volume. Enthalpy includes both the internal energy of a system and the energy required to create space for the system against an external pressure. Therefore, the correct relationship between enthalpy, internal energy, pressure, and volume is H = U + PV. Choice B is incorrect as subtracting PV would not account for the work done against pressure. Choice C is incorrect as dividing U by PV doesn't represent the definition of enthalpy. Choice D is incorrect as dividing PV by U is not the correct relationship based on the definition of enthalpy.

2. An object with a charge of 3 μC is placed 30 cm from another object with a charge of 2 μC. What is the magnitude of the resulting force between the objects?

• A. 0.6 N
• B. 0.18 N
• C. 180 N
• D. 9 × 10−12 N

Correct answer: B

Rationale: To find the magnitude of the resulting force between two charges, we use Coulomb's Law: F = k × (|q1 × q2|) / r² Where: F is the force k is Coulomb’s constant (8.99 × 10⁹ N·m²/C²) q1 and q2 are the charges r is the distance between the charges Plugging in the values: F = (8.99 × 10⁹) × (3 × 10⁻⁶) × (2 × 10⁻⁶) / (0.3)² = 0.18 N. Therefore, the magnitude of the resulting force is 0.18 N.

3. 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.

4. An object with a charge of 4 μC is placed 1 meter from another object with a charge of 2 μC. What is the magnitude of the resulting force between the objects?

• A. 0.04 N
• B. 0.072 N
• C. 80 N
• D. 8 × 10−6 N

Correct answer: A

Rationale: To find the magnitude of the resulting force between two charges, we can use Coulomb's law, which states that the force is directly proportional to the product of the charges and inversely proportional to the square of the distance between them. The formula for Coulomb's law is: F = k × (|q1 × q2| / r²), where F is the force, k is the Coulomb constant, q1 and q2 are the charges, and r is the distance between the charges. Substituting the given values into the formula: F = (9 × 10⁹ N·m²/C²) × ((4 × 10⁻⁶ C) × (2 × 10⁻⁶ C) / (1 m)²) = 0.04 N. Therefore, the magnitude of the resulting force between the objects is 0.04 N.

5. A rock has a volume of 6 cm3 and a mass of 24 g. What is its density?

• A. 4 g/cm3
• B. 4 cm3/g
• C. 144 g/cm3
• D. 144 cm3/g

Correct answer: A

Rationale: Density is calculated by dividing the mass of an object by its volume. In this case, the mass of the rock is 24 g and its volume is 6 cm3. By dividing 24 g by 6 cm3, we find that the density of the rock is 4 g/cm3. Choice A is the correct answer because density is expressed in units of mass per unit volume (g/cm3). Choice B is incorrect as it represents the reciprocal of density. Choices C and D are significantly higher values and do not match the calculated density of the rock.

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