Nursing Elites

1. How does sunscreen protect the skin from harmful ultraviolet (UV) rays?

• A. By reflecting UV rays away from the skin
• B. By absorbing UV rays and converting them to heat
• C. By blocking UV rays completely
• D. By stimulating melanin production

Correct answer: B

Rationale: Sunscreen works by absorbing UV rays and converting them to heat. This mechanism helps to prevent the UV rays from penetrating the skin and causing damage such as sunburn, premature aging, and skin cancer. Reflecting UV rays away from the skin (option A) is not the primary function of sunscreen. While sunscreen does block UV rays, it does not do so completely (option C) as some UV rays may still penetrate the skin. Sunscreen does not stimulate melanin production (option D) as a means of protecting the skin from UV rays.

2. An object is moving in a circle at constant speed. Is there a net force acting on it?

• A. Yes, always
• B. No, never
• C. Only if its speed is changing
• D. Only if its direction is changing

Correct answer: D

Rationale: When an object is moving in a circle at a constant speed, there is a net force acting on it. This net force is directed towards the center of the circle and is responsible for continuously changing the direction of the object's velocity, even though the speed remains constant. Therefore, the correct answer is D because the net force is required to change the direction of the object's motion in a circular path. Choices A, B, and C are incorrect because the presence of a net force is necessary to continuously change the object's direction as it moves in a circular path, irrespective of changes in speed.

3. What is the common name for the compound CH₃COOH?

• A. Acetic acid
• B. Formic acid
• C. Butyric acid
• D. Propionic acid

Correct answer: A

Rationale: The compound CH₃COOH is commonly known as acetic acid. Acetic acid is a clear, colorless liquid with a sour taste and a pungent smell. It is a weak acid found in vinegar and is used in the production of various chemicals. Formic acid, butyric acid, and propionic acid are different organic acids with distinct chemical structures and properties, but they are not the common name for the compound CH₃COOH.

4. What is the primary function of B cells in the immune system?

• A. Directly attacking and engulfing pathogens
• B. Producing antibodies specific to a pathogen
• C. Destroying infected body cells
• D. All of the above

Correct answer: B

Rationale: B cells are a type of white blood cell that primarily functions by producing antibodies specific to a pathogen. These antibodies play a crucial role in marking pathogens for destruction by other immune cells. While B cells are essential for the immune response, they do not directly attack and engulf pathogens or destroy infected body cells. These functions are carried out by other immune cells like macrophages and cytotoxic T cells. Therefore, the correct answer is B, as it accurately reflects the primary role of B cells in the immune system.

5. If a doctor diagnoses a patient with an impaired posterior pituitary gland, which of the following symptoms related to kidney function does the patient display?

• A. Thirst
• B. Tiredness
• C. Weight gain
• D. Concentrated urine

Correct answer: D

Rationale: When the posterior pituitary gland is impaired, there is decreased secretion of antidiuretic hormone (ADH). ADH plays a crucial role in regulating water reabsorption by the kidneys. A deficiency of ADH leads to the inability of the kidneys to concentrate urine, resulting in the production of dilute urine. Therefore, 'Concentrated urine' is the correct symptom associated with impaired posterior pituitary gland. Choices A, B, and C are incorrect. Thirst is more commonly associated with diabetes insipidus, tiredness could be a general symptom but not specifically related to kidney function, and weight gain is not a typical symptom of impaired posterior pituitary gland affecting kidney function.

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