Nursing Elites

1. When does work on an object occur?

• A. Only when the object's velocity changes
• B. Only when a force is applied to the object
• C. Whenever there is a force exerted on the object causing displacement
• D. Only when the object is lifted vertically

Correct answer: c

Rationale: Work is done when a force is applied to an object, causing it to move in the direction of the force.

2. Isotopes are variants of a single element that differ in:

• A. Having the same number of protons but varying numbers of neutrons
• B. Having the same number of neutrons but varying numbers of protons
• C. Having the same mass but different atomic numbers
• D. None of the above

Correct answer: A

Rationale: The correct answer is A: 'Having the same number of protons but varying numbers of neutrons.' Isotopes are atoms of the same element with the same number of protons (which determines the element) but different numbers of neutrons. This results in isotopes having slightly different atomic masses. Options B and C are incorrect because isotopes specifically refer to variations in the number of neutrons, not protons or atomic numbers. Option D is incorrect because isotopes do exist due to differences in neutron number.

3. In plant cells, what structure provides rigidity and support?

• A. Cell membrane
• B. Golgi apparatus
• C. Plastid
• D. Cell wall

Correct answer: D

Rationale: The correct answer is D: Cell wall. The cell wall is a rigid structure found in plant cells that provides support and protection. It is composed of cellulose and other materials, forming a tough outer layer that helps maintain the cell's shape and prevents it from bursting under pressure. The cell membrane (option A) is a semi-permeable barrier that surrounds the cell but does not provide rigidity. The Golgi apparatus (option B) is involved in sorting and packaging proteins. Plastids (option C) are organelles responsible for functions like photosynthesis and storage, but they do not provide rigidity and support like the cell wall does.

4. Laser light differs from typical light sources due to its properties of:

• A. Enhanced brightness only
• B. Monochromatic nature (single color) and coherence (synchronized waves)
• C. Increased velocity
• D. Limited visibility to the human eye

Correct answer: B

Rationale: The correct answer is B: Monochromatic nature (single color) and coherence (synchronized waves). Laser light is unique because it consists of a single color (monochromatic) and its waves are synchronized (coherent), unlike typical light sources which emit a range of colors and incoherent waves. This coherence allows laser light to stay focused over long distances, making it useful in various applications such as surgery, communication, and manufacturing. Enhanced brightness (A) is not the only distinguishing factor of laser light, as coherence and monochromatic nature are equally important. Increased velocity (C) and limited visibility to the human eye (D) are not properties that define laser light. Therefore, option B is the most accurate choice.

5. A ball is rolling across the floor and comes to a stop on its own. What force caused the ball to stop?

• A. Gravitational force
• B. Normal force from the floor
• C. Air resistance
• D. None of the above

Correct answer: C

Rationale: In the absence of other forces, air resistance will gradually slow down the ball until it stops.

6. What happens to the gravitational potential energy of an object as it falls freely?

• A. It decreases
• B. It increases
• C. It remains constant
• D. It becomes zero

Correct answer: a

Rationale: Gravitational potential energy decreases as an object falls freely due to a decrease in its height.

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