Nursing Elites

1. Half-life refers to the characteristic time it takes for:

• A. Radioactive intensity to completely disappear
• B. The number of neutrons in a nucleus to double
• C. The number of protons in a nucleus to change
• D. An isotope to decay by half of its initial quantity

Correct answer: D

Rationale: The correct answer is D: An isotope to decay by half of its initial quantity. The half-life of a substance is the time it takes for half of the initial quantity of radioactive atoms to decay. This is a characteristic property of each radioactive isotope and is used to determine the rate of decay of a substance. Option A is incorrect because radioactive intensity does not completely disappear in half-life, it only decreases by half. Options B and C are unrelated to the concept of half-life and do not accurately describe its definition.

2. Which part of the neuron receives signals from other neurons and conducts them toward the cell body?

• A. Axon
• B. Dendrite
• C. Synapse
• D. Myelin sheath

Correct answer: b

Rationale: The correct answer is B: Dendrite. Dendrites are the part of the neuron that receive signals from other neurons and conduct them toward the cell body. They have numerous branches and are covered in synapses, allowing them to receive signals from multiple neurons. The axon, on the other hand, conducts signals away from the cell body towards other neurons or to muscles or glands. The synapse is the junction between two neurons where communication occurs, and the myelin sheath is a fatty layer that insulates and speeds up the conduction of electrical impulses along the axon. Therefore, the dendrite is specifically designed to receive and integrate incoming signals, making it the correct answer in this case.

3. In the reaction 2Na + 2H2O → 2NaOH + H2, what is the limiting reactant when 3 moles of sodium react with 2 moles of water?

• A. Na
• B. H2O
• C. NaOH
• D. H2

Correct answer: a

Rationale: Sodium is the limiting reactant because it runs out first in a 1:1 ratio with water.

4. An ancient Egyptian pyramid has a square base with side lengths of 20 meters and a remaining height (after erosion) of 10 meters. Its original height was 30 meters. What was the volume of the pyramid in its original state?

• A. 12000 cu m
• B. 6000 cu m
• C. 18000 cu m
• D. 24000 cu m

Correct answer: A

Rationale: Use the formula for the volume of a pyramid with the original height and base area.

5. What is the SI unit of measurement for acceleration?

• A. Meters per second (m/s)
• B. Newton (N)
• C. Meters (m)
• D. Meters per second squared (m/s²)

Correct answer: d

Rationale: Acceleration is measured in meters per second squared (m/s²) in the SI unit system.

6. Which property of a wave determines its energy?

• A. Wavelength
• B. Amplitude
• C. Frequency
• D. Velocity

Correct answer: b

Rationale: Amplitude is directly related to the energy carried by a wave - higher amplitudes correspond to higher energy waves.

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