Nursing Elites

1. What phenomenon explains the formation of rainbows in the sky?

• A. Diffraction
• B. Interference
• C. Refraction and dispersion of sunlight by water droplets
• D. Reflection from clouds

Correct answer: C

Rationale: Rainbows are formed due to the refraction and dispersion of sunlight by water droplets in the atmosphere. When sunlight enters a water droplet, it is refracted, then internally reflected, and finally refracted again as it exits the droplet. This dispersion of light into its component colors creates the beautiful rainbow we see in the sky. Choice A, diffraction, involves bending of light around obstacles or through narrow openings, not the splitting of light into colors as seen in rainbows. Choice B, interference, refers to the phenomenon where two or more light waves overlap and interact, producing a pattern of light and dark bands, which is not the case with rainbows. Choice D, reflection from clouds, does not accurately describe the process involved in the formation of rainbows through refraction and dispersion of light by water droplets.

2. Which of the following organs functions as both an endocrine and exocrine gland?

• A. The kidney
• B. The spleen
• C. The pancreas
• D. The stomach

Correct answer: C

Rationale: The pancreas is the correct answer as it functions as both an endocrine and exocrine gland. The endocrine function involves secreting insulin and glucagon into the bloodstream to regulate blood sugar levels, while the exocrine function involves releasing digestive enzymes into the small intestine to aid in digestion. The kidney (Choice A) primarily functions in the excretory system by filtering blood and producing urine. The spleen (Choice B) is involved in the immune system and blood storage but does not have endocrine or exocrine functions. The stomach (Choice D) is mainly an organ of the digestive system, secreting gastric juices to aid in digestion, but it does not have a dual endocrine and exocrine function like the pancreas.

3. What is the stoichiometric coefficient of nitrogen (N2) in the balanced equation for the Haber process: N2 + 3H2 → 2NH3?

• A. 1
• B. 2
• C. 3
• D. 4

Correct answer: A

Rationale: In the balanced equation for the Haber process: N2 + 3H2 → 2NH3, the stoichiometric coefficient of nitrogen (N2) is 1. This means that one molecule of nitrogen reacts with three molecules of hydrogen to produce two molecules of ammonia. The coefficient '1' indicates the mole ratio of N2 in the reaction. Choice B, 2, is incorrect because it represents the coefficient for ammonia (NH3) in the balanced equation. Choice C, 3, is incorrect as it corresponds to the coefficient of hydrogen (H2). Choice D, 4, is not the correct stoichiometric coefficient for nitrogen (N2) in this equation.

4. What is the primary function of the kidneys?

• A. To digest food
• B. To filter blood and produce urine
• C. To absorb nutrients
• D. To transport oxygen

Correct answer: B

Rationale: The primary function of the kidneys is to filter blood and remove waste products from the body, producing urine in the process. This function helps in maintaining the body's internal environment stable, a process known as homeostasis. Option A, 'To digest food,' is incorrect as digestion primarily occurs in the gastrointestinal system, not in the kidneys. Option C, 'To absorb nutrients,' is also incorrect because nutrient absorption mainly takes place in the intestines. Option D, 'To transport oxygen,' is incorrect as the lungs and circulatory system are responsible for oxygen transport, not the kidneys.

5. Which hormone is produced by the thyroid gland?

• A. Insulin
• B. Thyroxine
• C. Adrenaline
• D. Cortisol

Correct answer: B

Rationale: The correct answer is B: Thyroxine. The thyroid gland produces thyroxine, a hormone essential for regulating metabolism. Insulin is produced by the pancreas to regulate blood sugar levels. Adrenaline is produced by the adrenal glands to prepare the body for the 'fight or flight' response. Cortisol is produced by the adrenal cortex in response to stress, not by the thyroid gland.

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