Nursing Elites

1. What term describes the phenomenon of two waves canceling each other out when they meet?

• A. Refraction
• B. Diffraction
• C. Destructive interference
• D. Constructive interference

Correct answer: C

Rationale: Destructive interference is the term used to describe the phenomenon when two waves meet and their amplitudes are such that they cancel each other out, resulting in a wave with a smaller amplitude or no wave at all. This cancellation effect occurs due to the waves being out of phase. This is in contrast to constructive interference, where two waves combine to produce a wave with a larger amplitude. Refraction is the bending of waves as they pass through different mediums, such as light passing through glass, while diffraction is the bending of waves around obstacles or through openings. In this case, the concept described in the question specifically aligns with destructive interference, making it the correct answer.

2. What is the half-life of a radioactive isotope, and how does it relate to its decay rate?

• A. The time it takes for half of the initial sample to decay.
• B. The time it takes for all of the sample to decay.
• C. The rate at which new isotopes are created.
• D. The energy released during decay.

Correct answer: A

Rationale: The half-life of a radioactive isotope is the time it takes for half of the initial sample to decay. After one half-life, half of the radioactive atoms have decayed. The decay rate, however, refers to the rate at which radioactive atoms decay, which is not directly related to the half-life. Choice B is incorrect because it does not correctly define the half-life. Choice C is incorrect as it refers to the creation of new isotopes, not the decay process. Choice D is incorrect as it describes the energy released during decay, which is not the same as the concept of half-life.

3. Which of the following is NOT a recognized mode of natural selection?

• A. Directional selection (favoring one extreme trait value on a spectrum)
• B. Disruptive selection (favoring both extreme trait values on a spectrum)
• C. Stabilizing selection (favoring the average trait value on a spectrum)
• D. Sexual selection (selection based on mate choice that influences reproductive success)

Correct answer: D

Rationale: A) Directional selection is a recognized mode of natural selection where one extreme trait value on a spectrum is favored over others, leading to a shift in the average trait value over time. B) Disruptive selection is a recognized mode of natural selection where both extreme trait values on a spectrum are favored over the average trait value, potentially causing the population to split into distinct groups. C) Stabilizing selection is a recognized mode of natural selection favoring the average trait value on a spectrum over extreme values, resulting in reduced genetic diversity. D) Sexual selection differs from traditional natural selection modes as it involves mate choice and competition for mates, not direct selection pressure on traits affecting survival and reproduction in the environment. Sexual selection can drive the evolution of traits enhancing an individual's attractiveness for mating purposes.

4. What is the independent variable in this experiment?

• A. Time
• B. Dog weight
• C. Dog species
• D. Dog food type

Correct answer: D

Rationale: The independent variable is the factor that is manipulated by the researcher to observe its effects on the dependent variable. In this experiment, the researcher is likely changing the type of dog food, and this manipulation is what impacts the outcome being measured. Therefore, 'Dog food type' is the independent variable. Choices A, B, and C do not represent the variable being intentionally changed by the researcher, making them dependent variables or other factors not directly controlled or manipulated in this experiment.

5. Which part of the brain is responsible for coordinating various sensory inputs, regulating sleep, and maintaining wakefulness?

• A. Cerebrum
• B. Hypothalamus
• C. Medulla oblongata
• D. Reticular formation

Correct answer: D

Rationale: The reticular formation is a network of neurons located in the brainstem that plays a crucial role in regulating sleep-wake cycles, coordinating various sensory inputs, and maintaining wakefulness. It acts as a filter for incoming sensory information and helps in directing attention to important stimuli. The other options, the cerebrum, hypothalamus, and medulla oblongata, are important structures in the brain but are not primarily responsible for the specific functions mentioned in the question. The cerebrum is mainly involved in higher brain functions such as thinking and voluntary movements. The hypothalamus is responsible for regulating body temperature, hunger, and thirst, among other functions. The medulla oblongata is essential for controlling vital autonomic functions like breathing and heart rate.

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