Nursing Elites

1. The unit for measuring luminous flux, which describes the perceived brightness of a light source by the human eye, is:

• A. Candela
• B. Lumen
• C. Lux
• D. Hertz

Correct answer: A

Rationale: The correct answer is B: Lumen. Luminous flux is the measure of the total quantity of visible light emitted by a source per unit time, measured in lumens. The candela (A) is the unit for luminous intensity, lux (C) is the unit for illuminance (luminous flux per unit area), and Hertz (D) is the unit for frequency. Therefore, in this question, the unit for measuring luminous flux is the lumen, as it specifically quantifies the perceived brightness of a light source by the human eye.

2. Adipose tissue, also known as fat, serves multiple functions. Which of these is NOT a function of adipose tissue?

• A. Insulation
• B. Energy storage
• C. Hormone production
• D. Muscle movement

Correct answer: D

Rationale: Adipose tissue plays various essential roles in the body, including insulation to help regulate body temperature, energy storage by storing excess energy in the form of fat, and hormone production such as leptin and adiponectin. However, adipose tissue is not directly responsible for muscle movement. Muscles are primarily responsible for movement, while adipose tissue provides cushioning and support around organs. Therefore, option D, 'Muscle movement,' is the correct answer as it does not align with the functions of adipose tissue.

3. Melanin, the pigment responsible for skin color, is produced by

• A. Keratinocytes (These cells produce keratin)
• B. Melanocytes
• C. Sebocytes (These cells produce sebum)
• D. Langerhans cells (These cells are part of the immune system)

Correct answer: B

Rationale: The correct answer is B: Melanocytes. Melanin, the pigment responsible for skin color, is produced by melanocytes, which are specialized cells located in the skin's epidermis. Melanocytes transfer melanin to keratinocytes, the predominant cell type in the epidermis, where it provides protection against UV radiation. Sebocytes produce sebum, an oily substance that helps moisturize the skin and hair. Langerhans cells are a type of immune cell that play a role in the skin's immune response. Therefore, the correct answer is B as melanocytes are specifically responsible for producing melanin.

4. An object is thrown at an angle. Which of the following forces acts HORIZONTALLY on the object during its flight?

• A. Gravitational force
• B. Normal force from the ground
• C. Air resistance
• D. The force of throwing

Correct answer: C

Rationale: Gravitational force acts downwards, normal force is perpendicular to motion at the launch point, and the throwing force is gone after release. Only air resistance acts continuously to oppose horizontal motion.

5. Which phenomenon describes the separation of light into its component colors when passing through a prism?

• A. Refraction
• B. Diffraction
• C. Dispersion
• D. Reflection

Correct answer: c

Rationale: Dispersion occurs when light passes through a prism, causing different wavelengths (colors) to separate due to their varying speeds through the medium.

6. The fatty sheath that insulates some nerve fibers and speeds up signal transmission is called the:

• A. Myelin sheath
• B. Dura mater
• C. Pia mater
• D. Arachnoid mater

Correct answer: A

Rationale: The correct answer is A: Myelin sheath. The myelin sheath is a fatty layer that surrounds and insulates certain nerve fibers. It acts as an electrical insulator, speeding up the transmission of nerve impulses along the axon. This insulation helps to prevent signal loss or interference, allowing for faster and more efficient communication between neurons. The other options, B: Dura mater, C: Pia mater, and D: Arachnoid mater, are all layers of the meninges that protect the brain and spinal cord, but they do not play a role in insulating nerve fibers for signal transmission like the myelin sheath does.

Similar Questions