Nursing Elites

1. Which hormone, produced by the pancreas, acts in opposition to insulin by increasing blood sugar levels?

• A. Insulin
• B. Glucagon
• C. Cortisol
• D. Thyroxine

Correct answer: B

Rationale: Glucagon is the correct answer. Produced by the pancreas, glucagon acts in opposition to insulin by increasing blood sugar levels. Glucagon promotes the breakdown of glycogen into glucose in the liver, leading to the release of glucose into the bloodstream. Insulin, on the other hand, lowers blood sugar levels by facilitating the uptake of glucose into cells. Cortisol is a hormone produced by the adrenal glands, not the pancreas, and is involved in stress response and metabolism. Thyroxine is a hormone produced by the thyroid gland and is primarily responsible for regulating metabolism.

2. How is blood pressure controlled by the body?

• A. By adjusting heart rate only
• B. By regulating blood volume
• C. By baroreceptors and hormones
• D. By adjusting body temperature

Correct answer: C

Rationale: Blood pressure is controlled by baroreceptors located in the aortic arch and carotid arteries that detect changes in blood pressure levels. When blood pressure is high, these receptors signal for adjustments to lower it. Additionally, hormones such as renin from the kidneys are released when blood pressure drops, further aiding in blood pressure regulation. Choice A is incorrect because blood pressure regulation involves more than just adjusting heart rate; it also includes vasodilation and vasoconstriction. Choice B is incorrect as while blood volume can impact blood pressure, it is not the primary mechanism of blood pressure control. Choice D is incorrect as body temperature regulation is a separate physiological process and not directly related to blood pressure control.

3. A spring with a spring constant of 100 N/m is stretched 0.2 m from its equilibrium position. What is the potential energy stored in the spring?

• A. 2 J
• B. 4 J
• C. 8 J
• D. 20 J

Correct answer: C

Rationale: The potential energy stored in a spring is given by the formula \(PE = \frac{1}{2}kx^2\), where \(k\) is the spring constant and \(x\) is the displacement from the equilibrium position. Substituting the given values, we get \(PE = \frac{1}{2} \times 100 \times (0.2)^2 = 8\) J.

4. How does polarization affect the intensity of light passing through a polarizing filter?

• A. All light passes through regardless of polarization.
• B. Light with the same polarization as the filter passes through, while others are blocked.
• C. Light with higher intensity passes through, while weaker light is blocked.
• D. The intensity is reduced for all light, regardless of polarization.

Correct answer: B

Rationale: A polarizing filter only allows light waves with a specific orientation (polarization) to pass through while blocking light waves with different orientations. Therefore, light with the same polarization as the filter will pass through, while light with different polarizations will be blocked. This results in a reduction in intensity for light passing through the polarizing filter. Choice A is incorrect because a polarizing filter selectively filters light based on its polarization. Choice C is incorrect as the intensity of light passing through is determined by its polarization, not solely its intensity. Choice D is incorrect because a polarizing filter affects light based on its polarization, not uniformly reducing the intensity for all light passing through.

5. A pendulum swings back and forth. What type of energy conversion occurs during its motion?

• A. Potential energy to kinetic energy and vice versa
• B. Thermal energy to mechanical energy and vice versa
• C. Chemical energy to electrical energy and vice versa
• D. Nuclear energy to radiant energy and vice versa

Correct answer: A

Rationale: As the pendulum swings back and forth, it undergoes a continuous conversion between potential energy (at the highest point of the swing) and kinetic energy (at the lowest point of the swing). At the highest point, the pendulum has maximum potential energy due to its height above the ground. As it swings down, this potential energy is converted into kinetic energy, which is the energy of motion. At the lowest point of the swing, the pendulum has maximum kinetic energy and minimal potential energy. The process repeats as the pendulum swings back in the opposite direction, demonstrating the conversion between potential and kinetic energy. Choices B, C, and D are incorrect because the energy conversion in a swinging pendulum primarily involves changes between potential and kinetic energy, not thermal, chemical, electrical, nuclear, or radiant energy.

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