Nursing Elites

1. A 120-volt heat lamp draws 25 amps of current. What is the lamp’s resistance?

• A. 96 ohms
• B. 104 ohms
• C. 150 ohms
• D. 4.8 ohms

Correct answer: D

Rationale: To find the resistance of the lamp, we use Ohm’s Law, which states that resistance (R) is equal to voltage (V) divided by current (I), expressed as: R = V / I. Given that the voltage (V) is 120 volts and the current (I) is 25 amps, we substitute these values into the formula: R = 120 V / 25 A = 4.8 ohms. Therefore, the resistance of the lamp is 4.8 ohms. Choice A, 96 ohms, is incorrect as it is not the result of the correct calculation. Choice B, 104 ohms, is incorrect as it does not match the calculated resistance. Choice C, 150 ohms, is incorrect as it is not the correct resistance value obtained through the calculation.

2. 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.

3. During adiabatic compression of a gas, what happens to its temperature?

• A. Remains constant
• B. Decreases
• C. Increases
• D. Becomes unpredictable without additional information

Correct answer: C

Rationale: During adiabatic compression, the gas's temperature increases. This is because no heat is exchanged with the surroundings, and all the work done on the gas results in an increase in internal energy. Choice A is incorrect because the temperature does not remain constant during adiabatic compression. Choice B is incorrect as the temperature does not decrease. Choice D is incorrect as the behavior of the gas's temperature during adiabatic compression is predictable based on the principles of thermodynamics.

4. A 5-kg block is suspended from a spring, causing the spring to stretch 10 cm from equilibrium. What is the spring constant for this spring?

• A. 4.9 N/cm
• B. 9.8 N/cm
• C. 49 N/cm
• D. 50 N/cm

Correct answer: C

Rationale: The spring constant (k) can be calculated using Hooke's Law formula: F = -kx, where F is the force applied, k is the spring constant, and x is the displacement from equilibrium. In this case, the force applied is equal to the weight of the block, F = mg, where m = mass of the block = 5 kg and g = acceleration due to gravity = 9.8 m/s^2. The displacement x = 10 cm = 0.1 m. Substituting the values, we have: 5 kg * 9.8 m/s^2 = k * 0.1 m. Solving for k gives k = 5 * 9.8 / 0.1 = 49 N/m. Therefore, the spring constant for this spring is 49 N/cm. Choice A (4.9 N/cm) is incorrect because it is one decimal place lower than the correct answer. Choice B (9.8 N/cm) is incorrect as it does not account for the correct calculation based on the given information. Choice D (50 N/cm) is incorrect because it is slightly higher than the accurate value obtained through the calculations.

5. When a fluid flows past a solid object, a thin layer of fluid adheres to the object's surface due to:

• A. Buoyancy
• B. Bernoulli's principle
• C. Boundary layer effect
• D. Surface tension minimization

Correct answer: C

Rationale: The boundary layer effect occurs when a thin layer of fluid near the surface of a solid adheres to it due to viscosity. This layer experiences a velocity gradient as the fluid farther from the surface moves faster, while the fluid closest to the surface is nearly stationary.

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