HESI Exams Quizlet Physics

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: 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: A

Rationale: The correct answer is A: 10 m/s. Velocity is calculated by dividing the distance traveled by the time taken. In this case, velocity = 100m / 10s = 10 m/s. Choice B, 90 m/s, is incorrect because it is not the accurate calculation. Choice C, 110 m/s, and choice D, 1,000 m/s, are both incorrect as they do not align with the correct formula for calculating velocity. The key is to remember that velocity is a vector quantity that includes both speed and direction, and in this case, we are only concerned with the speed of the object, making choice A the correct answer.

Correct Answer: A

Rationale: To find the current drawn, use the formula: Current (I) = Power (P) / Voltage (V). Substituting the values: I = 60 watts / 110 volts = 0.55 amperes (A). This is the correct answer. Other choices are incorrect as they do not match the calculated value. B: 1.83A, C: 50A, D: 6,600A are all significantly different from the calculated current of 0.55A, thus not the correct answer.

Correct Answer: C

Rationale: Step-by-step rationale: 1. Archimedes' principle states that the buoyant force on an object is equal to the weight of the fluid displaced. 2. Submarines adjust their buoyancy by changing the amount of water they displace, allowing them to submerge or resurface. 3. This control of buoyancy is crucial for submarines to navigate underwater efficiently while conserving energy. 4. Choice A is incorrect as density differences affect buoyancy, not causing objects to sink regardless. 5. Choice B is incorrect as airplane lift is generated by the Bernoulli principle and wing design, not Archimedes' principle. 6. Choice D is incorrect as helium balloons float due to buoyancy force exceeding their weight, not overcoming gravity.