Nursing Elites

1. A person pushes a box across a floor with a constant force. The box eventually comes to a stop due to friction. What happens to the work done by the person?

• A. It increases as the box moves further.
• B. It decreases as the box slows down.
• C. It remains constant throughout the motion.
• D. It becomes zero once the box stops.

Correct answer: C

Rationale: Work is defined as force multiplied by distance, and as long as the force remains constant, the work done increases proportionally to the distance moved, even if the box slows down due to friction.

2. Identify the spectator ions in the reaction: 2KCl + Pb(NO3)2 → 2KNO3 + PbCl2.

• A. K+ and NO3-
• B. K+ and Cl-
• C. Pb2+ and NO3-
• D. Pb2+ and Cl-

Correct answer: B

Rationale: Rationale: - In the reaction, potassium ions (K+) and chloride ions (Cl-) are present on both sides of the equation. They are not involved in the formation of the products and remain unchanged. - Lead ions (Pb2+) and nitrate ions (NO3-) are involved in the formation of the products potassium nitrate (KNO3) and lead(II) chloride (PbCl2). - Therefore, the spectator ions in this reaction are K+ and Cl-.

3. In the reaction 4Al + 3O2 → 2Al2O3, what is the mole ratio of aluminum to oxygen?

• A. 4:3
• B. 2:3
• C. 3:2
• D. 3:4

Correct answer: a

Rationale: The coefficients in the balanced equation represent the mole ratio, which is 4 moles of Al to 3 moles of O2.

4. The major site for nutrient absorption in the digestive system is the:

• A. Mouth
• B. Stomach
• C. Small intestine
• D. Large intestine

Correct answer: C

Rationale: The correct answer is C: Small intestine. The small intestine is the major site for nutrient absorption in the digestive system. It is where most of the digestion and absorption of nutrients from food takes place. The small intestine has villi and microvilli that increase its surface area, allowing for efficient absorption of nutrients like sugars, amino acids, and fatty acids into the bloodstream. The mouth is primarily responsible for mechanical digestion through chewing, while the stomach's main function is to break down food with enzymes and acids. The large intestine mainly absorbs water and electrolytes, with minimal nutrient absorption.

5. What is the difference between active and passive immunity?

• A. Active immunity is short-lived, while passive immunity is long-lasting.
• B. Active immunity involves the body's own immune response, while passive immunity provides immediate protection through antibodies from another source.
• C. Active immunity only protects against bacterial infections, while passive immunity works against both bacteria and viruses.
• D. Passive immunity requires repeated vaccinations, while active immunity is a one-time process.

Correct answer: A

Rationale: The correct answer is A: "Active immunity involves the body's own immune response, while passive immunity provides immediate protection through antibodies from another source." Active immunity is long-lasting because it involves the body's immune system producing memory cells that remember specific pathogens, providing long-term protection. Passive immunity, on the other hand, is short-lived as it involves receiving pre-formed antibodies from an external source, such as through maternal transfer or injection of antibodies, which do not create memory cells for long-lasting protection.

6. Which hormone, produced by the pineal gland, plays a role in regulating sleep-wake cycles and is often associated with the body's internal circadian rhythm?

• A. Melatonin
• B. Serotonin
• C. Dopamine
• D. Endorphin

Correct answer: a

Rationale: The correct answer is A: Melatonin. Melatonin is a hormone produced by the pineal gland that plays a crucial role in regulating sleep-wake cycles and is closely tied to the body's circadian rhythm. It is often referred to as the 'sleep hormone' because it helps signal to the body when it is time to sleep and wake up. Serotonin (option B) is a neurotransmitter that plays a role in mood regulation and happiness. Dopamine (option C) is involved in reward-motivated behavior and movement. Endorphins (option D) are neuropeptides that act as natural painkillers and contribute to feelings of pleasure. Therefore, Melatonin is the hormone associated with the body's internal circadian rhythm and sleep-wake cycles.

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