HESI Exams Quizlet Physics

Correct Answer: B

Rationale: The correct answer is B: Permeability is preferred. High permeability in the core of an electromagnet enhances its magnetic field strength by allowing more magnetic flux to pass through, increasing the efficiency of the electromagnet. Resistivity (choice A) would hinder current flow, reducing magnetic field strength. Permittivity (choice C) is related to electric fields, not magnetic fields. Dielectric strength (choice D) is the ability of a material to withstand electric fields, not directly related to enhancing magnetic properties.

Correct Answer: B

Rationale: To determine the power rating of the lamp, we use the formula Power = Energy / Time. Given the lamp consumes 60 Joules per second, the power rating is 60 Joules / 1 second = 60 Watts (Choice B). The other choices are incorrect because A is too low, C is not a valid unit for power, and D is not necessary as power can be calculated based on energy consumption alone.

Correct Answer: D

Rationale: The correct answer is D: To allow the circuit to open and close. A switch in a circuit functions by either completing or interrupting the flow of current. When the switch is closed, it provides a path for the current to flow, allowing the circuit to be operational. Conversely, when the switch is opened, it breaks the circuit, halting the flow of current. This on-off capability of a switch enables control over the circuit, making it a fundamental component in regulating the flow of electricity. Choices A, B, and C are incorrect because a switch does not reverse the direction of current, increase voltage, or alter the resistance of wires in a circuit.

Correct Answer: C

Rationale: The correct answer is C because reversible processes can be run in both directions with the same outcome, while irreversible processes cannot. In a reversible process, the system and surroundings can be restored to their original states after the process is reversed, maintaining equilibrium. This is not possible in irreversible processes, where energy dissipation and entropy generation lead to permanent changes. Choices A, B, and D are incorrect because reversible processes can involve heat transfer, do take time, and do not violate the first law of thermodynamics.

Correct Answer: A

Rationale: The correct answer is A: Q = cΔT. This equation represents the definition of specific heat capacity, where Q (heat transfer) is equal to the product of c (specific heat capacity) and ΔT (temperature change) for a unit mass of the material. This equation is derived from the formula for heat transfer, Q = mcΔT, by dividing both sides by mass 'm'. Therefore, the correct equation is Q = cΔT. Summary of other choices: B: Q = mcΔT - This is the formula for total heat transfer, not specific heat capacity. C: Q = c / mΔT - This equation does not accurately represent the relationship between specific heat capacity, heat transfer, temperature change, and mass. D: Q = ΔT / mc - This equation is not a correct representation of specific heat capacity and does not follow the standard formula.