Nursing Elites

1. The element responsible for the green color of leaves is:

• A. Magnesium
• B. Iron
• C. Copper
• D. Zinc

Correct answer: A

Rationale: Magnesium is the central element of chlorophyll, the pigment responsible for photosynthesis

2. A keystone species plays a critical role in an ecosystem because its removal would:

• A. Lead to a decrease in competition among other species
• B. Cause a slight increase in primary productivity
• C. Have a minimal impact on the overall ecosystem structure
• D. Disrupt the food web and cause cascading effects on other populations

Correct answer: D

Rationale: Rationale: Keystone species are species that have a disproportionately large effect on their environment relative to their abundance. They play a critical role in maintaining the structure and function of an ecosystem. If a keystone species is removed from an ecosystem, it can disrupt the food web by causing imbalances in predator-prey relationships. This disruption can lead to cascading effects on other populations within the ecosystem, potentially causing population declines or even extinctions. Therefore, the removal of a keystone species would have significant impacts on the overall ecosystem structure, making option D the correct answer.

3. A table top has dimensions of 75cm by 50cm. What is its perimeter if opposite sides are equal?

• A. 125cm
• B. 150cm
• C. 200cm
• D. 50cm

Correct answer: B

Rationale: Rationale: - Given that the table top has dimensions of 75cm by 50cm. - Since opposite sides are equal, the table top can be divided into two pairs of equal sides: 75cm and 50cm. - To find the perimeter, we add up all four sides: 75cm + 50cm + 75cm + 50cm = 250cm. - However, since opposite sides are equal, we only need to consider two sides: 75cm + 50cm = 125cm. - Therefore, the perimeter of the table top is 125cm + 125cm = 150cm. - Hence, the correct answer is B) 150cm.

4. In nuclear transmutation, a target nucleus is bombarded with a particle to create:

• A. A heavier isotope of the same element
• B. A lighter isotope of the same element
• C. An entirely new element
• D. A chain reaction of nuclear fission

Correct answer: C

Rationale: In nuclear transmutation, a target nucleus is bombarded with a particle to create an entirely new element. During this process, the target nucleus absorbs the incoming particle, resulting in changes to its atomic number and sometimes its mass number. These changes can lead to the creation of a different element altogether. This is a fundamental concept in nuclear chemistry and is used in various applications, including the creation of new isotopes for research or medical purposes. Options A and B are incorrect because transmutation involves creating a different element, not just a heavier or lighter isotope of the same element. Option D, a chain reaction of nuclear fission, is also incorrect as it refers to a different process where a nucleus splits into smaller fragments, releasing energy and more neutrons to sustain the chain reaction.

5. A spring is stretched and released, causing an object attached to it to oscillate. What determines the frequency of the oscillations?

• A. The mass of the object
• B. The stiffness of the spring
• C. The initial displacement of the object
• D. All of the above

Correct answer: B

Rationale: The stiffness of the spring. Frequency depends on the spring constant and the mass, but the mass term cancels out in the formula for simple harmonic motion, leaving only the spring constant.

6. What is the formula to calculate work?

• A. Work = Force × Distance
• B. Work = Mass × Velocity
• C. Work = Power × Time
• D. Work = Energy ÷ Time

Correct answer: a

Rationale: Work is calculated by multiplying force exerted on an object by the distance the object moves in the direction of the force.

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