TEAS 7 practice test science

Correct Answer: B

Rationale: The correct answer is B: To increase lung compliance. Surfactant is a substance produced by type II alveolar cells in the lungs that reduces surface tension in the alveoli. This reduction in surface tension helps to increase lung compliance, making it easier for the lungs to expand and contract during breathing. Improved lung compliance is essential for efficient gas exchange in the respiratory system, facilitating oxygen uptake and carbon dioxide removal. Choices A, C, and D are incorrect because surfactant does not trap dust particles, produce mucus, or generate oxygen during respiration. Instead, its primary function lies in reducing surface tension to prevent alveolar collapse and improve lung compliance for optimal gas exchange.

Correct Answer: D

Rationale: Elasticity refers to a material's ability to resist deformation and return to its original shape after stress is applied. It is the property that resists a change in shape. Density is the mass per unit volume of a substance. Mass is the amount of matter in an object, while inertia is the tendency of an object to resist changes in its state of motion. Viscosity, not mentioned in the question, is the resistance of a fluid to flow, not shape change.

Correct Answer: B

Rationale: The amplitude of a wave is directly related to its intensity or loudness. In general, the larger the amplitude of a wave, the greater its intensity or loudness. This relationship is due to the fact that the amplitude of a wave represents the maximum displacement of particles in the medium from their rest position. The greater the displacement, the more energy the wave carries, leading to higher intensity or louder sound. Choice A is incorrect because the relationship between amplitude and intensity is direct, not inverse. Choice C is incorrect as there is a clear relationship between amplitude and intensity. Choice D is incorrect as amplitude primarily affects intensity or loudness, not frequency.

Correct Answer: A

Rationale: Molality (m) is the unit used to express concentration as a mass of solute per unit volume of solution. It is calculated by dividing the mass of solute in grams by the mass of the solvent in kilograms. Molality is preferred over molarity when there are large temperature variations as it is temperature-independent, making it a more accurate measure of concentration. Molarity (B) is the unit used to express concentration as moles of solute per liter of solution, weight percent (C) is the mass of solute per 100 parts of the total mass of the solution, and parts per million (D) is used to express very small concentrations where 1 ppm is equivalent to 1 mg of solute per liter of solution.

Correct Answer: B

Rationale: Photons are not charged particles; they are packets of energy that exhibit wave-particle duality, meaning they can behave as both particles and waves. While photons are part of the electromagnetic spectrum, they are not electromagnetic waves themselves but rather discrete energy packets. They are not always absorbed by matter; they can be reflected, transmitted, or scattered.