Nursing Elites

1. When magnesium metal reacts with hydrochloric acid, hydrogen gas is produced. What evidence suggests a chemical reaction is occurring?

• A. A change in color
• B. The formation of a gas
• C. Dissolving in a liquid
• D. No change in temperature

Correct answer: B

Rationale: The correct answer is B: 'The formation of a gas.' When magnesium metal reacts with hydrochloric acid, hydrogen gas is produced as one of the products. The formation of a gas is a clear indicator of a chemical reaction taking place. This is known as a gas evolution reaction, where a gas is produced as a result of a chemical reaction. The other options do not specifically indicate a chemical reaction. A change in color or dissolving in a liquid could occur in physical changes as well, and no change in temperature does not necessarily rule out a chemical reaction as some reactions are endothermic or exothermic.

2. In which medium does light propagate at its highest speed?

• A. Air
• B. Water
• C. Glass
• D. Diamond

Correct answer: A

Rationale: The correct answer is A: 'Air.' Light propagates at its highest speed in a vacuum, which is nearly the same as in air. In a vacuum, light travels at its maximum speed of approximately 299,792 kilometers per second. When light enters a medium like air, water, glass, or diamond, its speed decreases due to interactions with atoms and molecules in the medium. Among the options given, air is the closest medium to a vacuum in terms of light speed. Water, glass, and diamond have higher refractive indices than air, causing light to travel slower in these mediums. This is why air allows light to propagate at its highest speed compared to water, glass, and diamond.

3. Antigen-antibody binding is the principle behind:

• A. Vaccination
• B. Disinfection
• C. Sterilization
• D. antibiotic resistance

Correct answer: A

Rationale: Rationale: Antigen-antibody binding is the principle behind vaccination. When a vaccine containing antigens (weakened or killed pathogens) is introduced into the body, the immune system produces antibodies that bind to these antigens. This binding triggers an immune response, leading to the production of memory cells that provide immunity against future infections by the same pathogen. Vaccination helps the body develop immunity without causing the disease itself, thereby protecting individuals from infectious diseases. Disinfection and sterilization involve different processes to eliminate or reduce pathogens on surfaces or objects. Antibiotic resistance is a phenomenon where bacteria evolve to resist the effects of antibiotics and is not directly related to antigen-antibody binding.

4. The professor explained the concept clearly. What is the past participle of the verb "explain"?

• A. explains
• B. explaining
• C. explained
• D. explanation

Correct answer: C

Rationale: The past participle is used to form verb tenses and passive voice constructions.

5. You need to paint a rectangular swimming pool with dimensions 8m by 5m and a depth of 2m. Considering only the interior walls and floor (not the top), how much paint do you need (assume one can of paint covers 10 sq m)?

• A. 56 sq m
• B. 72 sq m
• C. 88 sq m
• D. 104 sq m

Correct answer: C

Rationale: Calculate the areas of each wall and the floor, sum them up, and subtract the area of the water surface (top). Divide the final area by the coverage area per can to determine the number of cans needed.

6. Which phenomenon describes the bending of light as it travels from one medium to another with differing densities?

• A. Reflection
• B. Refraction
• C. Diffraction
• D. Dispersion

Correct answer: B

Rationale: The correct answer is B: Refraction. Refraction is the phenomenon that describes the bending of light as it travels from one medium to another with differing densities. When light passes from one medium to another, such as from air to water, its speed changes, causing it to bend. This bending of light is what we observe when a pencil appears bent in a glass of water. Reflection, on the other hand, is the bouncing back of light when it hits a surface. Diffraction refers to the bending of light around obstacles, and dispersion is the separation of light into its different colors. Therefore, in this case, refraction is the most appropriate term to describe the bending of light as it moves between media with different densities.

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