Nursing Elites

1. Which type of waves do not require a medium for propagation?

• A. Transverse waves
• B. Longitudinal waves
• C. Electromagnetic waves
• D. Surface waves

Correct answer: C

Rationale: Electromagnetic waves do not require a medium for propagation as they consist of oscillating electric and magnetic fields that can travel through a vacuum. This property allows electromagnetic waves, such as light, radio waves, and X-rays, to propagate through space. In contrast, transverse and longitudinal waves require a medium (solid, liquid, or gas) for propagation. Transverse waves have vibrations perpendicular to the direction of energy transfer, while longitudinal waves have vibrations parallel to the direction of energy transfer. Surface waves, which are a combination of transverse and longitudinal waves, also need a medium for propagation. Understanding the distinction between these wave types is essential in various fields, including physics and communication technologies.

2. Which structure in the heart is responsible for preventing the backflow of blood from the left ventricle into the left atrium?

• A. Aortic valve
• B. Pulmonary valve
• C. Tricuspid valve
• D. Mitral valve

Correct answer: D

Rationale: The mitral valve, also known as the bicuspid valve, is located between the left atrium and the left ventricle of the heart. Its primary function is to prevent the backflow of blood from the left ventricle into the left atrium during ventricular contraction. The aortic valve (A) prevents the backflow of blood from the aorta into the left ventricle, the pulmonary valve (B) prevents the backflow of blood from the pulmonary artery into the right ventricle, and the tricuspid valve (C) prevents the backflow of blood from the right ventricle into the right atrium. Understanding the functions of these heart valves is crucial in maintaining proper blood flow through the heart and preventing regurgitation of blood into the wrong chambers.

3. What is the molar mass of Ca(NO3)2?

• A. 74.1 g/mol
• B. 132.1 g/mol
• C. 164.1 g/mol
• D. 78.1 g/mol

Correct answer: B

Rationale: To calculate the molar mass of Ca(NO3)2, we add up the individual atomic masses of its elements: Ca (40.08) + 2N (2 * 14.01) + 6O (6 * 16.00) = 40.08 + 28.02 + 96.00 = 164.1 g/mol. Therefore, the correct answer is 164.1 g/mol (Choice C). Choice A (74.1 g/mol) is incorrect as it does not account for the correct sum of atomic masses. Choice B (132.1 g/mol) is the correct molar mass calculation for Ca(NO3)2. Choice D (78.1 g/mol) is incorrect and does not reflect the accurate molar mass of the compound.

4. What happens during expiration?

• A. The diaphragm contracts and the thoracic cavity expands.
• B. The diaphragm relaxes and the thoracic cavity contracts.
• C. The thoracic cavity expands, increasing pressure.
• D. The diaphragm relaxes and moves upward.

Correct answer: B

Rationale: The correct answer is B. During expiration, the diaphragm relaxes, causing the thoracic cavity to contract. As the thoracic cavity decreases in size, the pressure inside the lungs increases, leading to air flowing out of the lungs. This process helps to expel carbon dioxide-rich air from the body. Choices A, C, and D are incorrect. In choice A, the diaphragm contracting and the thoracic cavity expanding describes inspiration, not expiration. Choice C is incorrect because during expiration, the thoracic cavity actually decreases in size. Choice D is incorrect as the diaphragm moving upward is not a typical movement associated with expiration.

5. Where is the major site for nutrient absorption in the digestive system?

• A. Mouth
• B. Stomach
• C. Small intestine
• D. Large intestine

Correct answer: C

Rationale: The small intestine is recognized as the major site for nutrient absorption in the digestive system. It plays a crucial role in the digestion and absorption of nutrients from food. The small intestine's villi and microvilli provide a large surface area specialized for absorbing nutrients like carbohydrates, proteins, fats, vitamins, and minerals. This efficient absorption process is essential for supplying the body with the necessary nutrients for energy production, growth, and overall functioning. The mouth is primarily involved in the initial stages of digestion through mechanical and chemical breakdown of food. The stomach aids in further mechanical and chemical digestion but is not the primary site for nutrient absorption. The large intestine's main function is to absorb water and electrolytes, not nutrients.

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