Nursing Elites

1. A convex lens is characterized by its ability to:

• A. Converge light rays
• B. Diverge light rays
• C. Focus sound waves
• D. Create virtual images only

Correct answer: A

Rationale: The correct answer is A: 'Converge light rays.' A convex lens is thicker in the center and thinner at the edges, causing light rays passing through it to converge or come together at a focal point. This ability is what enables convex lenses to bend light rays inward, focusing them to produce clear images. Options B and C are incorrect because convex lenses do not diverge light rays or focus sound waves. Option D is also incorrect as convex lenses can create both real and virtual images based on the position of the object with respect to the lens. Therefore, the main characteristic of a convex lens is its ability to converge light rays to form focused images.

2. What happens to the concentration of hydrogen ions (\([H^+]\)) in a solution as the pH increases?

• A. Increases
• B. Decreases
• C. Remains constant
• D. Becomes neutral

Correct answer: B

Rationale: As the pH increases, the concentration of hydrogen ions decreases. The relationship is inversely proportional

3. The ability of a substance to dissolve in another is called:

• A. Solubility
• B. Miscibility
• C. Immiscibility
• D. Reactivity

Correct answer: A

Rationale: Solubility refers to the extent to which one substance can dissolve in another to form a homogeneous solution.

4. What is the name of the structure that packages DNA in eukaryotic cells?

• A. Nucleosome
• B. Chromatin
• C. Histone
• D. Centromere

Correct answer: A

Rationale: Rationale: - A nucleosome is the basic structural unit of DNA packaging in eukaryotic cells. It consists of DNA wrapped around a core of histone proteins. - Chromatin refers to the complex of DNA and proteins found in the nucleus of a eukaryotic cell, including nucleosomes. - Histones are the proteins around which DNA is wrapped to form nucleosomes. - Centromere is a region of a chromosome where the two sister chromatids are joined and to which spindle fibers attach during cell division.

5. What is the name of the radioactive isotope commonly used in medical imaging techniques like PET scans?

• A. Uranium-235
• B. Plutonium-239
• C. Potassium-40
• D. Fluorine-18

Correct answer: D

Rationale: Fluorine-18 is the radioactive isotope commonly used in medical imaging techniques like PET scans. It is often used in the form of fluorodeoxyglucose (FDG) to detect areas of increased metabolic activity in the body, such as in cancer cells. Uranium-235 and Plutonium-239 are not typically used in medical imaging, and Potassium-40 is a naturally occurring radioactive isotope found in the human body but is not commonly used in medical imaging techniques.

6. A lampshade is shaped like a frustum of a cone, with base diameters of 20cm and 10cm and a height of 15cm. What is its volume?

• A. 625 cu cm
• B. 1250 cu cm
• C. 1875 cu cm
• D. 2500 cu cm

Correct answer: C

Rationale: This requires dividing the frustum into two cones and calculating their individual volumes before subtracting them. The formula for a cone frustum involves the radii of both bases and the height.

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