Nursing Elites

1. What is the principle behind the phenomenon of refraction, where waves bend when entering a new medium?

• A. Change in wavelength
• B. Change in frequency
• C. Change in wave speed
• D. None of the above

Correct answer: C

Rationale: Refraction occurs due to a change in wave speed when waves enter a new medium. As waves travel from one medium to another, their speed changes, causing them to bend. This change in speed is responsible for the bending of waves during refraction. It is not the change in wavelength or frequency that causes refraction, but rather the change in speed as waves move through different mediums. Therefore, the correct answer is the change in wave speed (Choice C). Choices A and B are incorrect as refraction is not primarily influenced by changes in wavelength or frequency, but by changes in wave speed. Choice D is also incorrect as there is a specific principle, which is the change in wave speed, behind the phenomenon of refraction.

2. Rusting of iron is an example of

• A. Endothermic reaction
• B. Exothermic reaction
• C. Single displacement reaction
• D. Photochemical reaction

Correct answer: A

Rationale: The rusting of iron is an endothermic reaction. This means that it absorbs heat from its surroundings to occur. Rusting involves the slow oxidation of iron in the presence of oxygen and water. As energy is absorbed during this process, it is classified as an endothermic reaction. Choice B, an exothermic reaction, releases heat instead of absorbing it, which is not the case in rusting. Choices C and D are unrelated to the process of rusting and do not involve the absorption of heat from the surroundings.

3. Which type of bond involves the complete transfer of electrons between atoms?

• A. Covalent bond
• B. Ionic bond
• C. Metallic bond
• D. Hydrogen bond

Correct answer: B

Rationale: The correct answer is B, Ionic bond. Ionic bond involves the complete transfer of electrons from one atom to another, resulting in the formation of cations and anions. This transfer leads to the creation of strong electrostatic attraction between the oppositely charged ions. Covalent bonds, on the other hand, involve the sharing of electrons between atoms to achieve stability. Metallic bonds are formed in metals, where a sea of delocalized electrons surrounds positively charged metal ions, contributing to the metal's properties. Hydrogen bonds are intermolecular forces that occur between a hydrogen atom and a highly electronegative atom like oxygen or nitrogen, not involving the complete transfer of electrons.

4. What is the primary function of the strong nuclear force?

• A. Binding electrons in atomic orbitals
• B. Binding protons and neutrons within the nucleus
• C. Mediating the attractive force between opposite charges
• D. Mediating the repulsive force between like charges

Correct answer: B

Rationale: The strong nuclear force primarily functions to bind protons and neutrons within the nucleus. It is responsible for overcoming the electrostatic repulsion between positively charged protons, holding the nucleus together. Choices A, C, and D are incorrect because the strong nuclear force specifically acts on nucleons (protons and neutrons) within the nucleus, not on electrons in atomic orbitals or charges outside the nucleus.

5. Which type of chemical reaction produces a salt?

• A. An oxidation reaction
• B. A neutralization reaction
• C. A synthesis reaction
• D. A decomposition reaction

Correct answer: B

Rationale: The correct answer is B, a neutralization reaction. In a neutralization reaction, an acid and a base react to produce a salt and water. This process involves the combination of H+ ions from the acid and OH- ions from the base to form water, while the remaining ions combine to form a salt. Therefore, a neutralization reaction is the specific type of chemical reaction that produces a salt. Choices A, C, and D are incorrect. An oxidation reaction involves the loss of electrons, a synthesis reaction involves the formation of a compound from simpler substances, and a decomposition reaction involves the breakdown of a compound into simpler substances. None of these reactions directly lead to the production of a salt, making them incorrect choices in this context.

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