Nursing Elites

1. Which element is used in fluorescent lamps and emits ultraviolet light when excited?

• A. Mercury
• B. Neon
• C. Argon
• D. Krypton

Correct answer: A

Rationale: Mercury is the correct element used in fluorescent lamps to emit ultraviolet light when excited. When an electric current passes through the mercury vapor inside the lamp, it generates ultraviolet (UV) light. This UV light then excites the phosphors coated on the inner surface of the lamp, causing them to emit visible light. Neon, argon, and krypton are not commonly used in fluorescent lamps for this purpose. Neon is primarily used in neon signs, argon is used in incandescent and fluorescent bulbs for inertia gas, and krypton is mainly used in certain types of specialized light bulbs for its specific properties.

2. What phenomenon is responsible for the mirage effect seen in deserts?

• A. Diffraction
• B. Refraction
• C. Interference
• D. Polarization

Correct answer: B

Rationale: Refraction is the bending of light as it passes from one medium to another of different density. In deserts, the temperature gradient causes light to bend, creating the mirage effect where distant objects appear distorted or displaced. Diffraction refers to the bending of light around obstacles or apertures, not the cause of mirages. Interference involves the superposition of two or more waves, which is not the mechanism behind mirages. Polarization refers to the orientation of light waves in a specific plane and is not responsible for the mirage effect in deserts. Therefore, the correct answer is refraction.

3. When a certain plant is introduced into an area, and the population of a certain insect species declines, what can be concluded from this?

• A. The plant is toxic to the insect in question.
• B. The plant competes with and drives out plants that the insect feeds on.
• C. The insect population was declining anyway; the fact that it happened when the plant was introduced is a coincidence.
• D. All of these explanations may be possible; further investigation is necessary to determine which is true.

Correct answer: D

Rationale: The given scenario presents multiple possible explanations for the decline in the insect population with the introduction of a particular plant. It could be due to the plant being toxic to the insect (Option A), competing with and driving out plants that the insect feeds on (Option B), or the decline could be coincidental with the plant introduction as the insect population was already decreasing (Option C). Without further investigation and evidence, it is not possible to definitively determine which explanation is correct. Therefore, all of these possibilities may be true, and thorough investigation is necessary to reach a conclusive conclusion.

4. What are Mendel's laws?

• A. Law of inheritance, law of expression
• B. Law of segregation, law of independent assortment
• C. Law of dominance, law of recessiveness
• D. Law of mutation, law of crossing over

Correct answer: B

Rationale: The correct answer is B. Mendel's laws consist of the law of segregation, which states that each parent passes one allele for each trait, and the law of independent assortment, which explains that genes for different traits are inherited independently. Choice A is incorrect because 'law of expression' is not one of Mendel's laws. Choice C is incorrect because 'law of dominance' and 'law of recessiveness' do not represent the two main laws proposed by Mendel. Choice D is incorrect because 'law of mutation' and 'law of crossing over' are not part of Mendel's original laws.

5. Which group of elements is known for their vibrant colors and is commonly used in fireworks?

• A. Noble gases
• B. Alkali metals
• C. Halogens
• D. Transition metals

Correct answer: D

Rationale: The correct answer is D: Transition metals. Transition metals are known for their vibrant colors and are commonly used in fireworks due to their ability to emit specific colors of light. The diverse electronic configurations of transition metals allow them to produce a variety of hues, making them ideal for creating colorful displays in fireworks. Choice A, Noble gases, do not typically produce vibrant colors in fireworks as they are colorless and odorless gases. Choice B, Alkali metals, are not known for their colorful displays in fireworks. Choice C, Halogens, can produce colors in fireworks, but they are not as commonly used for their vibrant hues compared to transition metals.

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