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. Which structure in the heart is responsible for preventing the backflow of blood from the left ventricle into the left atrium?

• A. Aortic valve
• B. Pulmonary valve
• C. Tricuspid valve
• D. Mitral valve

Correct answer: D

Rationale: The mitral valve, also known as the bicuspid valve, is located between the left atrium and the left ventricle of the heart. Its primary function is to prevent the backflow of blood from the left ventricle into the left atrium during ventricular contraction. The aortic valve (A) prevents the backflow of blood from the aorta into the left ventricle, the pulmonary valve (B) prevents the backflow of blood from the pulmonary artery into the right ventricle, and the tricuspid valve (C) prevents the backflow of blood from the right ventricle into the right atrium. Understanding the functions of these heart valves is crucial in maintaining proper blood flow through the heart and preventing regurgitation of blood into the wrong chambers.

3. What does the number of protons in the nucleus of an atom determine?

• A. Mass number
• B. Atomic number
• C. Isotope
• D. Valence electron count

Correct answer: B

Rationale: The number of protons in the nucleus of an atom is referred to as the atomic number. This atomic number is crucial as it uniquely identifies an element and determines its position on the periodic table. The mass number, on the other hand, represents the sum of protons and neutrons in an atom's nucleus. Isotopes are variants of elements with the same number of protons but differing numbers of neutrons. Valence electron count pertains to the number of electrons in the outermost energy level of an atom, which influences its chemical behavior.

4. What does nuclear binding energy represent?

• A. Separate an electron from its atom
• B. Separate protons and neutrons within a nucleus
• C. Cause nuclear fission
• D. Induce nuclear fusion

Correct answer: B

Rationale: Nuclear binding energy represents the energy required to hold protons and neutrons together within a nucleus. This energy is needed to overcome the electrostatic repulsion between positively charged protons and keep the nucleus stable. Choices A, C, and D are incorrect. Choice A relates to ionization energy, which is the energy required to remove an electron from an atom. Choices C and D refer to nuclear reactions (fission and fusion), which involve processes different from the concept of nuclear binding energy.

5. What is the structural and functional unit of the kidney responsible for filtering blood?

• A. Nephron
• B. Ureter
• C. Urethra
• D. Bladder

Correct answer: A

Rationale: The nephron is the correct answer. It is the structural and functional unit of the kidney responsible for filtering blood. The nephron consists of a renal corpuscle (glomerulus and Bowman's capsule) and a renal tubule. Within the nephron, blood is filtered to form urine, which is then carried to the ureter for excretion from the body. Choices B, C, and D are incorrect because the ureter, urethra, and bladder are not involved in the filtration of blood in the kidney. Instead, they are parts of the urinary system responsible for transporting and storing urine.

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