Nursing Elites

1. The ability of optical fibers to transmit light signals around bends is primarily due to:

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

Correct answer: B

Rationale: The correct answer is B: Refraction. Optical fibers transmit light signals around bends primarily through the process of refraction. Refraction occurs when light passes from one medium to another, causing it to change direction. In optical fibers, the core material has a higher refractive index than the cladding, which causes light to be reflected internally along the fiber. This phenomenon allows light signals to travel through the fiber even around bends without significant loss. Reflection (Option A) involves light bouncing off a surface, which is not the main mechanism in optical fibers. Diffraction (Option C) refers to the bending of light waves around obstacles and is not the main reason for light transmission in optical fibers. Polarization (Option D) relates to the orientation of light waves, which is not the primary factor enabling light transmission around bends in optical fibers.

2. A decorative globe has a diameter of 25cm. What is its total surface area?

• A. 1570 sq cm
• B. 1963 sq cm
• C. 2513 sq cm
• D. 3142 sq cm

Correct answer: B

Rationale: Use the formula for surface area of a sphere: 4 * π * (radius)^2, where radius is half the diameter. Calculate the radius (12.5cm) and substitute: 4 * π * (12.5cm)^2 ≈ 1963 sq cm.

3. A scientist observes a new chemical reaction and proposes a mechanism for how it occurs. What is the BEST way to test this mechanism?

• A. Simulate the reaction using computer models.
• B. Design experiments to manipulate predicted intermediate steps.
• C. Compare the reaction to similar known reactions.
• D. Publish the mechanism in a scientific journal.

Correct answer: B

Rationale: Designing experiments to manipulate predicted intermediate steps is the best way to test the proposed mechanism because it directly tests the validity of the proposed mechanism by manipulating the specific steps involved. This approach allows for empirical validation of the proposed mechanism and provides concrete evidence to support or refute it. Simulating the reaction using computer models may provide some insights but does not directly test the mechanism. Comparing the reaction to similar known reactions can provide some context but does not directly test the proposed mechanism. Publishing the mechanism in a scientific journal is important for sharing findings but does not constitute a test of the mechanism itself.

4. What is the valve that prevents blood from flowing back from the left ventricle into the left atrium?

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

Correct answer: B

Rationale: The correct answer is B: Mitral valve. The mitral valve, also known as the bicuspid valve, is located between the left atrium and the left ventricle. Its primary function is to prevent the backflow of blood from the left ventricle into the left atrium during ventricular contraction. The tricuspid valve is located between the right atrium and right ventricle, the aortic valve is located between the left ventricle and the aorta, and the pulmonic valve is located between the right ventricle and the pulmonary artery. Therefore, the mitral valve is specifically responsible for preventing backflow in the left side of the heart, making it the correct answer.

5. Two coherent light waves with a slight phase difference interfere. What determines the resulting intensity of the combined wave?

• A. The individual intensities of the waves
• B. The wavelength of the waves
• C. The distance between the waves
• D. The color of the waves

Correct answer: A

Rationale: The intensity of the resulting wave depends on the individual intensities and the phase difference between the interfering waves. Constructive interference leads to higher intensity, while destructive interference leads to lower intensity.

6. Which organ is responsible for filtering blood and removing waste products?

• A. Liver
• B. Kidneys
• C. Spleen
• D. Pancreas

Correct answer: B

Rationale: The correct answer is B: Kidneys. The kidneys are responsible for filtering blood and removing waste products from the body through the production of urine. The liver plays a role in detoxifying the blood and producing bile, while the spleen is involved in filtering blood and removing old or damaged red blood cells. The pancreas is primarily responsible for producing digestive enzymes and regulating blood sugar levels. Therefore, the kidneys are the specific organ dedicated to the filtration of blood and removal of waste products, making them the correct choice in this question.

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