Nursing Elites

1. What term describes the bending of waves around obstacles or through openings?

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

Correct answer: c

Rationale: Diffraction occurs when waves bend around obstacles or spread after passing through small openings.

2. Vaccines work by:

• A. Directly killing pathogens
• B. Introducing weakened or inactive versions of pathogens to trigger immune response
• C. Stimulating production of specific antibodies immediately
• D. None of the above

Correct answer: B

Rationale: The correct answer is B: Introducing weakened or inactive versions of pathogens to trigger an immune response. Vaccines work by exposing the immune system to a harmless version of a pathogen, which allows the body to recognize and develop a defense against the pathogen without causing illness. This process stimulates the immune system to produce memory cells that can quickly recognize and attack the pathogen if encountered in the future. Vaccines do not directly kill pathogens (option A) or immediately stimulate the production of specific antibodies (option C). Therefore, option B is the most accurate description of how vaccines work.

3. The Gram stain is a differential staining technique used to classify bacteria based on their cell wall composition. Gram-positive bacteria appear

• A. Pink
• B. Blue
• C. Red
• D. Purple

Correct answer: D

Rationale: Rationale: The Gram stain is a differential staining technique that divides bacteria into two groups based on their cell wall composition: Gram-positive and Gram-negative. Gram-positive bacteria have a thick layer of peptidoglycan in their cell walls, which retains the crystal violet stain used in the Gram staining procedure. As a result, Gram-positive bacteria appear purple under the microscope after staining. In contrast, Gram-negative bacteria have a thinner peptidoglycan layer and an outer membrane that can be penetrated by the counterstain safranin, causing them to appear pink or red. Blue is not typically used to describe the color of bacteria in a Gram stain.

4. Which of the following factors does NOT affect the rate of dissolution of a solute in a solvent?

• A. Temperature
• B. Pressure
• C. Surface area
• D. Particle size

Correct answer: B

Rationale: Pressure does not affect the rate of dissolution of a solute in a solvent. The factors that do affect the rate of dissolution include temperature, surface area, and particle size. Temperature generally increases the rate of dissolution as it provides more energy for the solute particles to break apart and mix with the solvent. Increasing the surface area of the solute by grinding it into smaller particles or increasing its contact area with the solvent can also speed up dissolution. Similarly, reducing the particle size of the solute can increase the rate of dissolution by providing more surface area for interaction with the solvent.

5. You need to repaint a cylindrical water tank with a diameter of 2 meters and a height of 3 meters. Assuming one can of paint covers 10 sq m, how many cans do you need (consider only the exterior surface)?

• A. 6 cans
• B. 9 cans
• C. 12 cans
• D. 15 cans

Correct answer: C

Rationale: Calculate the surface area of the cylinder and divide by the coverage area per can.

6. Which of the following is NOT a characteristic of a chemical reaction?

• A. Formation of new substances
• B. Release or absorption of energy
• C. Change in color
• D. Change in temperature

Correct answer: C

Rationale: While color change can be an indicator of a chemical reaction, it's not always present, and some reactions occur without a visible color change.

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