Nursing Elites

1. Which term describes the resistance of a substance to being hammered into different shapes?

• A. Viscosity
• B. Ductility
• C. Malleability
• D. Conductivity

Correct answer: C

Rationale: Malleability is the property that allows a substance to be hammered or rolled into thin sheets without breaking. It is the opposite of brittleness. Ductility refers to the ability of a material to be drawn into thin wires, not hammered into shapes. Viscosity is the measure of a fluid's resistance to flow, indicating how thick or sticky it is, not related to shaping by hammering. Conductivity refers to the ability of a material to conduct electricity or heat, not resistance to being hammered into different shapes.

2. In a covalent bond, the shared electrons:

• A. Are completely transferred to one atom.
• B. Spend more time closer to the more electronegative atom.
• C. Remain equidistant between the two atoms.
• D. Do not influence the bond strength.

Correct answer: B

Rationale: In a covalent bond, the shared electrons spend more time closer to the more electronegative atom. Electronegativity is the ability of an atom to attract electrons in a chemical bond. The more electronegative atom exerts a stronger pull on the shared electrons, causing them to be closer to that atom. Choice A is incorrect because in a covalent bond, electrons are shared, not completely transferred. Choice C is incorrect as the shared electrons are not equidistant but are closer to one atom due to electronegativity differences. Choice D is incorrect because shared electrons play a significant role in determining the bond strength by the strength of the bond formed through electron sharing.

3. What is an electrically charged atom called?

• A. Ion
• B. Isotope
• C. Molecule
• D. Compound

Correct answer: A

Rationale: An ion is an atom that has gained or lost electrons, resulting in a positive or negative charge, making it electrically charged. This term specifically refers to atoms with a net electrical charge. Isotopes are atoms of the same element with different numbers of neutrons, not electrically charged. Molecules are formed when atoms bond together, but they are not necessarily charged. Compounds are substances composed of different elements bonded together, but they may not be electrically charged.

4. T cells in the immune system can be categorized into different types. What type of T cell directly kills infected body cells?

• A. Helper T cells
• B. Cytotoxic T cells
• C. Regulatory T cells
• D. Memory T cells

Correct answer: B

Rationale: Cytotoxic T cells directly kill infected body cells by recognizing specific antigens on the surface of infected cells and releasing cytotoxic substances to induce cell death, eliminating the infected cells. Helper T cells assist in coordinating the immune response, regulatory T cells help maintain immune tolerance, and memory T cells mount a faster and stronger response upon re-exposure to a previously encountered antigen. Therefore, the correct answer is cytotoxic T cells as they play a crucial role in directly targeting and destroying infected cells.

5. In nuclear physics, the term 'magic number' refers to specific numbers of protons or neutrons that contribute to:

• A. Increased nuclear instability
• B. Enhanced radioactive decay rates
• C. Exceptional stability of the nucleus
• D. All of the above

Correct answer: C

Rationale: In nuclear physics, the term 'magic number' refers to specific numbers of protons or neutrons that lead to exceptional stability of the nucleus. These 'magic numbers' correspond to completely filled nuclear energy levels, resulting in increased stability rather than instability. Choice A, 'Increased nuclear instability,' is incorrect as magic numbers actually contribute to stability. Choice B, 'Enhanced radioactive decay rates,' is also incorrect as magic numbers do not affect decay rates but rather stability. Therefore, the correct answer is choice C, as magic numbers contribute to the exceptional stability of the nucleus.

Similar Questions