Nursing Elites

1. Define 'friction' in terms of opposing motion.

• A. A force that increases motion
• B. A force that accelerates motion
• C. A force that opposes motion
• D. A force that creates motion

Correct answer: C

Rationale: Friction is a force that opposes motion. When two surfaces are in contact, friction acts in the opposite direction to the motion or the potential motion between the two surfaces. It resists the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. Friction hinders or prevents motion rather than promoting it. Choices A, B, and D are incorrect as they suggest that friction increases, accelerates, or creates motion, which is inaccurate. The correct definition of friction is that it opposes motion, making choice C the most appropriate option.

2. When calcium chloride (CaCl2) dissolves in water, it separates into its ions (Ca2+ and Cl-). This is an example of:

• A. Chemical change
• B. Physical change
• C. Precipitation
• D. Neutralization

Correct answer: B

Rationale: When calcium chloride dissolves in water, it separates into its ions without forming a new substance, which is characteristic of a physical change. A physical change involves alterations in the substance's physical properties without changing its chemical composition. In this scenario, the chemical formula of calcium chloride remains unchanged, and only its physical state changes by creating ions in the solution. Therefore, the dissolution of calcium chloride in water is an example of a physical change. Choice A, 'Chemical change,' is incorrect because no new substances are formed during the dissolution process. Choice C, 'Precipitation,' is incorrect as precipitation involves the formation of an insoluble solid when two solutions react. Choice D, 'Neutralization,' is incorrect as it refers to a reaction between an acid and a base to form salt and water, which is not the case in the given scenario.

3. What is the term for the process of a liquid changing into a gas?

• A. Evaporation
• B. Boiling
• C. Condensation
• D. Sublimation

Correct answer: A

Rationale: The correct answer is 'Evaporation.' Evaporation is the process by which a liquid changes into a gas at any temperature, while boiling specifically refers to the rapid vaporization of a liquid only at its boiling point. Condensation is the opposite process of gas turning into a liquid, and sublimation is the direct transition from solid to gas without passing through the liquid phase.

4. What are enzymes?

• A. Building blocks of muscle
• B. Biological catalysts
• C. Energy source
• D. Antibodies

Correct answer: B

Rationale: Enzymes are biological catalysts, not building blocks of muscle. They speed up chemical reactions in living organisms without being consumed in the process. Enzymes are not an energy source or antibodies. They play a crucial role in various biological processes by lowering the activation energy required for a reaction to occur, thereby increasing the rate of the reaction.

5. What is the primary function of the myelin sheath that surrounds some axons in the nervous system?

• A. To initiate nerve impulses
• B. To transmit sensory information
• C. To speed up the transmission of nerve impulses
• D. To connect neurons at synapses

Correct answer: C

Rationale: The primary function of the myelin sheath is to speed up the transmission of nerve impulses. The myelin sheath acts as an insulating layer around the axon, allowing for faster conduction of electrical impulses along the nerve fiber. This insulation prevents the electrical signal from dissipating or 'leaking' out, which helps in the rapid and efficient transmission of nerve impulses along the axon. Choice A is incorrect because the myelin sheath does not initiate nerve impulses; it helps in conducting them. Choice B is incorrect as the myelin sheath's main role is not in transmitting sensory information but rather in facilitating the transmission of nerve impulses. Choice D is incorrect because the myelin sheath's function is not to connect neurons at synapses; instead, it is primarily involved in enhancing the speed of nerve impulse transmission.

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