HESI Exams Quizlet Physics

Correct Answer: A

Rationale: Semiconductors fall between conductors and insulators in terms of electrical conductivity because they have conductivity levels higher than insulators but lower than conductors. Conductors have high conductivity due to abundant free electrons, while insulators have very low conductivity due to the lack of free electrons. Semiconductors can conduct electricity under certain conditions by manipulating the number of free electrons through doping or applying electric fields. Therefore, choice A is correct. Choices B, C, and D are incorrect because they do not accurately represent the conductivity levels of semiconductors in relation to other materials.

Correct Answer: C

Rationale: When a charged particle moves through a vacuum at a constant speed, it generates both an electric and magnetic field. This phenomenon is described by Maxwell's equations in electromagnetism. The moving charge creates a changing electric field which, in turn, induces a magnetic field according to Faraday's law of electromagnetic induction. This interplay between electric and magnetic fields is fundamental to electromagnetism. Choice A is incorrect as the moving charge does not only generate an electric field. Choice B is incorrect because the moving charge does not only generate a magnetic field. Choice D is incorrect because a moving charged particle always generates both electric and magnetic fields due to the fundamental principles of electromagnetism.

Correct Answer: B

Rationale: Step-by-step rationale for choice B (Repulsion to magnetic fields) being correct: 1. Diamagnetic materials create small, weak opposing magnetic fields when in the presence of an external magnetic field. 2. These opposing fields cause repulsion between the material and the external field. 3. This repulsion is a characteristic feature of diamagnetism, distinguishing it from other types of magnetism. 4. Therefore, choice B is correct. Summary of why other choices are incorrect: A: Diamagnetic materials are not attracted to magnetic fields, so this choice is incorrect. C: Diamagnetic materials do not amplify magnetic fields, so this choice is incorrect. D: Diamagnetic materials do not show indifference to magnetic fields but rather exhibit repulsion, making this choice incorrect.

Correct Answer: C

Rationale: The correct answer is C: "It operates isothermally at the hot and cold reservoir temperatures." This statement is NOT true about a Carnot cycle. A Carnot cycle consists of four reversible processes: isothermal expansion, adiabatic expansion, isothermal compression, and adiabatic compression. During the isothermal process, the working substance absorbs heat at the hot reservoir temperature and releases heat at the cold reservoir temperature. This process does not occur at the exact temperature of the reservoirs; rather, it occurs at a range of temperatures within each reservoir. As such, the statement that it operates isothermally at the hot and cold reservoir temperatures is incorrect. In summary, the other choices are incorrect because: A is true as efficiency is determined by the reservoir temperatures, B is true as it is a reversible cycle, and D is true as the Carnot cycle is the most efficient heat engine between the same two temperatures.

Correct Answer: B

Rationale: The correct answer is B: Decrease. When one side of the U-tube manometer is connected to a pressurized system, the pressure on that side will be higher, causing the fluid level to decrease due to the increase in pressure. This is because the pressure difference between the two sides of the manometer causes the fluid to move towards the side with higher pressure. Choice A is incorrect because the fluid level will not remain the same in response to the pressure change. Choice C is incorrect as the fluid level will decrease, not increase. Choice D is incorrect as the type of fluid used does not affect how the fluid level changes in response to pressure.