HESI A2 Physics Practice Test

Correct Answer: D

Rationale: The surrounding air is NOT considered a part of the system when analyzing a power plant as it acts as the environment outside the system boundary. The system typically includes components directly involved in the energy conversion process, such as the fuel, working fluid, and turbine. The surrounding air, while it may have an impact on the plant's operations, is not a component within the system boundary and does not play a direct role in the energy conversion process. Choices A, B, and C are all integral parts of the power plant system as they are directly involved in the conversion of energy from the fuel to electricity.

Correct Answer: D

Rationale: The correct answer is D: Refraction. Refraction is the phenomenon of light bending as it passes through different mediums, such as a prism. This occurs due to the change in speed of light when transitioning from one medium to another, causing the light to change direction. Reflection (A) is the bouncing back of light off a surface, not bending. Electrical conduction (B) is the movement of electric charges through a material, not related to light behavior. Diffraction (C) is the bending of light around obstacles or through small openings, not specifically related to prisms.

Correct Answer: A

Rationale: The Prandtl number (Pr) is defined as the ratio of momentum diffusivity (kinematic viscosity) to thermal diffusivity in a fluid. Therefore, the correct answer is A, viscosity and thermal diffusivity. This is because Pr provides a measure of the relative importance of momentum diffusivity to thermal diffusivity in a fluid flow. Choices B, C, and D are incorrect because they do not directly relate to the definition and concept of the Prandtl number. B relates to the equation of state, C relates to intermolecular forces, and D relates to flow characteristics, none of which are directly linked to the Prandtl number.

Correct Answer: B

Rationale: Faraday's law of electromagnetic induction states that a changing magnetic field in a conductor induces an electromotive force (EMF) according to the Faraday's law equation. This induced EMF creates a current flow in the conductor. The other choices are incorrect because an increase in resistance (choice A) would oppose the current induced by the changing magnetic field, static electric charge (choice C) is not related to induction, and a decrease in capacitance (choice D) is not directly affected by a changing magnetic field.

Correct Answer: A

Rationale: The correct answer is A: Mass. Mass is an intrinsic property of a substance that remains constant regardless of temperature changes. This is because mass is a measure of the amount of matter in an object and does not depend on external factors like temperature. Volume (B) can change with temperature as substances expand or contract. Phase (C) can change with temperature shifts, such as from solid to liquid or gas. Solubility (D) can also be influenced by temperature, as it affects how well a substance dissolves in a solvent. Therefore, mass is the only property that remains constant regardless of temperature variations.