Nursing Elites

1. What is the function of valves in arteries?

• A. To maintain high blood pressure for the proper diffusion of nutrients in capillaries.
• B. To prevent backflow of blood due to high pressure away from the heart.
• C. As a vestigial trait from evolution, like the appendix, that serves no purpose.
• D. Valves are absent in arteries but present in veins.

Correct answer: B

Rationale: Valves in arteries serve the crucial function of preventing backflow of blood. Arteries carry blood at high pressure away from the heart, and the valves ensure that blood flows in one direction, towards the capillaries, to maintain efficient circulation. Without these valves, there would be a risk of blood flowing backward, compromising the effectiveness of blood circulation in the body. Choices A, C, and D are incorrect. Choice A incorrectly suggests that valves maintain high blood pressure for nutrient diffusion in capillaries, which is not their function. Choice C inaccurately compares valves to vestigial traits, like the appendix, implying they serve no purpose, which is untrue. Choice D is incorrect as valves are indeed present in arteries to regulate blood flow, not just in veins.

2. Which of the following represents different types of electromagnetic waves based on their wavelengths and frequencies?

• A. Visible light, X-rays, radio waves, gamma rays
• B. Sound waves, water waves, seismic waves, shock waves
• C. Longitudinal waves, transverse waves, mechanical waves, non-mechanical waves
• D. None of the above

Correct answer: A

Rationale: Electromagnetic waves are categorized based on their wavelengths and frequencies. Visible light, X-rays, radio waves, and gamma rays are all examples of electromagnetic waves with distinct wavelengths and frequencies. The correct answer choice, A, accurately represents different types of electromagnetic waves. Sound waves, water waves, seismic waves, and shock waves are mechanical waves that propagate through a medium via particle interactions, not electromagnetic waves. Longitudinal waves, transverse waves, mechanical waves, and non-mechanical waves are classifications based on the nature of the wave propagation and do not relate to the types of electromagnetic waves which are differentiated by their electromagnetic properties.

3. Iron is a transition metal, which means it often forms a cation with a charge of what?

• A. 2- or 3-
• B. 1-
• C. 2+ or 3+
• D. 1+

Correct answer: C

Rationale: The correct answer is C: 2+ or 3+. Transition metals, like iron, are known for their ability to exhibit variable oxidation states. This characteristic allows them to form cations with charges such as 2+ or 3+. Specifically, iron can form cations with these charges due to the varying electron configurations in its d-orbitals. The other choices are incorrect because transition metals typically form positively charged cations, not negatively charged ones. Additionally, while iron can form cations with charges of 2+ or 3+, it does not commonly form cations with charges of 1- or 1+. Transition metal cations play a crucial role in forming coordination complexes with ligands, highlighting their importance in various chemical reactions.

4. What is the primary difference between ionic and metallic bonding?

• A. Ionic bonds involve electron transfer, while metallic bonds involve electron sharing.
• B. Ionic bonds are weak and directional, while metallic bonds are strong and non-directional.
• C. Ionic bonds exist between metals and non-metals, while metallic bonds exist only between metals.
• D. Ionic bonds form discrete molecules, while metallic bonds form extended structures.

Correct answer: B

Rationale: Ionic bonds involve electron transfer, where one atom completely donates an electron to another, resulting in discrete molecules. On the other hand, metallic bonds are non-directional and strong, formed by a 'sea' of delocalized electrons shared among all metal atoms. This shared electron cloud allows for strong bonding throughout the entire material, making metallic bonds non-directional and strong compared to the directional and weaker nature of ionic bonds. Choice A is incorrect because metallic bonds do not involve electron sharing but rather the sharing of a sea of delocalized electrons. Choice C is incorrect as metallic bonds can also exist between metal atoms, not just between metals and non-metals. Choice D is incorrect because metallic bonds do not form discrete molecules but rather extended structures due to the sharing of electrons among all metal atoms.

5. 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.

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