Nursing Elites

1. How does sunscreen protect the skin from harmful ultraviolet (UV) rays?

• A. By reflecting UV rays away from the skin
• B. By absorbing UV rays and converting them to heat
• C. By blocking UV rays completely
• D. By stimulating melanin production

Correct answer: B

Rationale: Sunscreen works by absorbing UV rays and converting them to heat. This mechanism helps to prevent the UV rays from penetrating the skin and causing damage such as sunburn, premature aging, and skin cancer. Reflecting UV rays away from the skin (option A) is not the primary function of sunscreen. While sunscreen does block UV rays, it does not do so completely (option C) as some UV rays may still penetrate the skin. Sunscreen does not stimulate melanin production (option D) as a means of protecting the skin from UV rays.

2. Which of the following factors would increase the solubility of a gas in a liquid?

• A. Decreasing temperature
• B. Increasing pressure
• C. Decreasing surface area
• D. Increasing particle size

Correct answer: B

Rationale: The correct answer is increasing pressure. According to Henry's Law, the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas above the liquid. Therefore, increasing pressure would force more gas molecules into the liquid, leading to an increase in solubility. Conversely, decreasing temperature, decreasing surface area, and increasing particle size would not directly impact the solubility of a gas in a liquid. Decreasing temperature typically decreases solubility as gases are less soluble at lower temperatures. Decreasing surface area and increasing particle size are related to surface area and not the pressure above the liquid, thus not affecting solubility as pressure does.

3. How is power related to work and time?

• A. Power = Work ÷ Time
• B. Power = Work × Time
• C. Power = Work + Time
• D. Power = Work - Time

Correct answer: A

Rationale: Power is defined as the rate at which work is done or the amount of work done per unit of time. The correct formula to relate power, work, and time is Power = Work ÷ Time. This formula shows that power is calculated by dividing the amount of work done by the time taken to do that work, indicating the rate at which work is being done. Choice B (Power = Work × Time) is incorrect because multiplying work and time does not yield a measure of power. Choice C (Power = Work + Time) is incorrect as adding work and time does not define power. Choice D (Power = Work - Time) is also incorrect because subtracting work and time does not relate to the concept of power.

4. The liver plays a vital role in digestion. What is one of the main functions of the liver in the digestive system?

• A. Physical breakdown of food
• B. Production of digestive enzymes
• C. Storage and processing of nutrients
• D. Elimination of waste products

Correct answer: C

Rationale: The correct answer is C: Storage and processing of nutrients. The liver plays a crucial role in processing nutrients absorbed from the small intestine, storing glycogen, vitamins, and minerals, and regulating blood sugar levels by releasing or storing glucose as needed. Choices A, B, and D are incorrect because the physical breakdown of food primarily occurs in the mouth and stomach, the production of digestive enzymes is mainly carried out by the pancreas and small intestine, and the elimination of waste products is primarily managed by the large intestine and kidneys, not the liver.

5. Which statement correctly matches the valve with its function in the heart?

• A. The aortic valve allows oxygenated blood to flow from the left ventricle to the rest of the body.
• B. The mitral valve opens to allow blood flow from the left atrium to the left ventricle.
• C. The pulmonic valve allows deoxygenated blood to flow from the right ventricle to the pulmonary artery.
• D. The tricuspid valve allows deoxygenated blood to flow from the right atrium to the right ventricle.

Correct answer: A

Rationale: The correct answer is A. The aortic valve allows oxygenated blood to flow from the left ventricle to the rest of the body. When the left ventricle contracts, the aortic valve opens to allow blood to be pumped into the aorta, the body's main artery that carries oxygen-rich blood to various parts of the body. Choices B, C, and D are incorrect because they do not match the described functions of the mitral, pulmonic, and tricuspid valves, respectively. The mitral valve controls the flow of blood between the left atrium and left ventricle, the pulmonic valve regulates the flow of blood from the right ventricle to the pulmonary artery, and the tricuspid valve manages the blood flow between the right atrium and right ventricle.

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