Nursing Elites

1. How many neutrons are in an atom of the following element with a mass number of 50?

• A. 38
• B. 88
• C. 50
• D. 126

Correct answer: C

Rationale: Neutrons are found in the nucleus of an atom along with protons. To determine the number of neutrons in an atom, subtract the atomic number (number of protons) from the mass number. In this case, the mass number given is 50. Since the atomic number is not specified, we can infer it from the choices provided. The mass number of an element represents the total sum of protons and neutrons in the nucleus. Therefore, the number of neutrons in this atom would also be 50, as the mass number is equivalent to the combined number of protons and neutrons, making choice C the correct answer. Choices A, B, and D are incorrect as they do not match the given mass number of 50.

2. What happens to the frequency of a wave if its wavelength decreases while the speed remains constant?

• A. Frequency decreases
• B. Frequency increases
• C. Frequency remains constant
• D. Frequency becomes zero

Correct answer: B

Rationale: The correct answer is B: Frequency increases. Frequency and wavelength are inversely proportional in a wave with a constant speed. When the wavelength decreases while the speed remains constant, the frequency must increase to maintain the constant speed of the wave. This relationship is governed by the equation: speed = frequency x wavelength. Choice A is incorrect as frequency increases when wavelength decreases. Choice C is incorrect as the frequency changes in this scenario. Choice D is incorrect as the frequency does not become zero but increases when the wavelength decreases.

3. What is the function of white blood cells?

• A. To transport oxygen
• B. To fight infection
• C. To carry oxygen
• D. To produce antibodies

Correct answer: B

Rationale: White blood cells play a crucial role in the immune system by fighting infection and protecting the body from foreign invaders. Choice A, 'To transport oxygen,' is incorrect because red blood cells are responsible for transporting oxygen. Choice C, 'To carry oxygen,' is also inaccurate for the same reason. Choice D, 'To produce antibodies,' while related to the immune system, is not the primary function of white blood cells, as their main role is to directly combat infections.

4. Which cells myelinate neurons in the PNS?

• A. Oligodendrocytes
• B. Astrocytes
• C. Schwann cells
• D. Microglia

Correct answer: C

Rationale: Schwann cells are the glial cells responsible for myelinating neurons in the peripheral nervous system (PNS). They form the myelin sheath around axons, which helps in the conduction of electrical impulses. Oligodendrocytes, on the other hand, myelinate neurons in the central nervous system (CNS). Astrocytes primarily provide support for neuronal function by regulating the chemical environment around neurons and maintaining the blood-brain barrier. Microglia are part of the immune response in the CNS, where they act as the resident macrophages, playing a role in immune surveillance and response to injury or disease. Therefore, the correct answer is Schwann cells (Choice C) as they specifically myelinate neurons in the PNS, differentiating them from the other cell types mentioned in the choices.

5. Which of the following chambers of the heart receives blood returning from the lungs during pulmonary circulation?

• A. left atrium
• B. right atrium
• C. left ventricle
• D. right ventricle

Correct answer: A

Rationale: The correct answer is A, the left atrium. During pulmonary circulation, oxygenated blood returns from the lungs to the heart and enters the left atrium through the pulmonary veins. The left atrium then contracts, pushing this oxygen-rich blood into the left ventricle. The left ventricle subsequently pumps this oxygenated blood out to the rest of the body through the aorta. Choices B, C, and D are incorrect because the right atrium receives deoxygenated blood from the body, the left ventricle receives oxygenated blood from the left atrium, and the right ventricle pumps deoxygenated blood to the lungs for oxygenation, respectively.

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