Nursing Elites

1. Which part of the eye controls the amount of light that enters the eye?

• A. Cornea
• B. Iris
• C. Retina
• D. Lens

Correct answer: B

Rationale: The iris is the correct answer as it controls the amount of light that enters the eye by adjusting the size of the pupil. The cornea is responsible for focusing light onto the retina, the retina detects light at the back of the eye, and the lens helps in further focusing light onto the retina. The iris, through changing the size of the pupil, regulates the amount of light reaching the eye, making it the part that controls the entry of light.

2. What is the oxidation state of carbon in CH4?

• A. +1
• B. -1
• C. +2
• D. -4

Correct answer: D

Rationale: In CH4 (methane), carbon is bonded to four hydrogen atoms. Hydrogen has an oxidation state of +1. Since the overall charge of CH4 is 0, the oxidation state of carbon must be -4 to balance the charges. Each hydrogen contributes an oxidation state of +1, resulting in a total of +4 from hydrogen atoms. To achieve a total oxidation state of 0 for the molecule, carbon must have an oxidation state of -4 to offset the contribution from hydrogen. Therefore, the correct answer is -4. Choices A, B, and C are incorrect: +1 is the oxidation state of hydrogen, -1 is not the oxidation state of carbon in methane, and +2 is not the correct oxidation state of carbon in CH4.

3. In the context of optical fibers, chromatic dispersion refers to:

• A. The total internal reflection of light
• B. The spreading of light pulses due to different colors traveling at slightly different speeds
• C. The bending of light at the fiber core-cladding interface
• D. The absorption of light by the fiber material

Correct answer: B

Rationale: Chromatic dispersion in optical fibers refers to the spreading of light pulses due to different colors (wavelengths) traveling at slightly different speeds. This phenomenon can cause the different components of a light pulse to arrive at the receiver at slightly different times, leading to signal distortion. Choice A is incorrect because total internal reflection refers to the phenomenon where light is reflected back into the medium it originated from when hitting the boundary at an angle greater than the critical angle. Choice C is incorrect as it describes the principle of light being guided within an optical fiber through total internal reflection at the core-cladding interface. Choice D is incorrect as the absorption of light by the fiber material does not relate to chromatic dispersion.

4. Are red hair and a height of six feet part of an individual's genotype or phenotype?

• A. Red hair is part of the phenotype; height is part of the genotype.
• B. Red hair is part of the genotype; height is part of the phenotype.
• C. Both characteristics describe his genotype.
• D. Both characteristics describe his phenotype.

Correct answer: D

Rationale: In the context of genetics, genotype refers to an individual's genetic makeup, while phenotype refers to the observable characteristics resulting from the interaction of the genotype with the environment. Red hair and a height of six feet are observable characteristics, making them part of the individual's phenotype. Therefore, both red hair and height are aspects of the individual's phenotype. Choices A and B are incorrect as they incorrectly assign one characteristic to the genotype and the other to the phenotype, which is not accurate. Choice C is incorrect as it states that both characteristics describe the genotype, which is inaccurate as they are observable traits. The correct answer is D, as both red hair and height are observable traits or characteristics, falling under the definition of phenotype in genetics.

5. What is the length of DNA that can code for a particular protein?

• A. Chromosome
• B. Nucleotide
• C. Gene
• D. Ribosome

Correct answer: C

Rationale: The correct answer is C: Gene. A gene is a specific segment of DNA that contains the information necessary to produce a particular protein. Genes are responsible for coding proteins, and each gene carries the instructions for a specific protein. Chromosomes consist of many genes and are not a specific length that codes for a protein. Nucleotides are the building blocks of DNA and are not a length that codes for a protein. Ribosomes are cellular organelles involved in protein synthesis and do not directly code for proteins.

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