Nursing Elites

1. What happens to the momentum of an object when there is no external force acting upon it?

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

Correct answer: C

Rationale: When there is no external force acting upon an object, the law of conservation of momentum dictates that the momentum of the object remains constant. This means that the momentum does not increase or decrease; it stays the same. Choice A is incorrect because momentum does not increase. Choice B is incorrect because momentum does not decrease. Choice D is incorrect as momentum does not become zero; it remains constant as per the conservation law. Therefore, the correct answer is C, as the object's momentum is unchanged in the absence of external forces.

2. In the context of optical fibers, chromatic dispersion refers to:

• A. The total internal reflection of light
• B. The spreading of light pulses due to different colors traveling at slightly different speeds
• C. The bending of light at the fiber core-cladding interface
• D. The absorption of light by the fiber material

Correct answer: B

Rationale: Chromatic dispersion in optical fibers refers to the spreading of light pulses due to different colors (wavelengths) traveling at slightly different speeds. This phenomenon can cause the different components of a light pulse to arrive at the receiver at slightly different times, leading to signal distortion. Choice A is incorrect because total internal reflection refers to the phenomenon where light is reflected back into the medium it originated from when hitting the boundary at an angle greater than the critical angle. Choice C is incorrect as it describes the principle of light being guided within an optical fiber through total internal reflection at the core-cladding interface. Choice D is incorrect as the absorption of light by the fiber material does not relate to chromatic dispersion.

3. Which part of the brain is responsible for coordinating muscle movements, maintaining balance, and posture?

• A. Cerebrum
• B. Cerebellum
• C. Medulla oblongata
• D. Thalamus

Correct answer: B

Rationale: The correct answer is B, the cerebellum. The cerebellum plays a crucial role in coordinating muscle movements, maintaining balance, and posture. It receives inputs from sensory systems, the spinal cord, and other brain regions to fine-tune motor movements. The cerebrum, choice A, is primarily involved in higher brain functions like thinking and decision-making. The medulla oblongata, choice C, controls essential functions such as breathing and heart rate. The thalamus, choice D, serves as a relay center for sensory information but is not directly responsible for coordinating muscle movements, balance, or posture.

4. What are the four chambers of the heart?

• A. Right atrium, left atrium, right ventricle, left ventricle
• B. Right atrium, left atrium, right ventricle, left atrium
• C. Left atrium, right ventricle, left ventricle, right atrium
• D. Left atrium, right atrium, left ventricle, right ventricle

Correct answer: A

Rationale: The correct answer is A: Right atrium, left atrium, right ventricle, left ventricle. The heart consists of four chambers: the right atrium, left atrium, right ventricle, and left ventricle. Blood flows from the body into the right atrium, then to the right ventricle, where it is pumped to the lungs for oxygenation. Oxygenated blood returns to the left atrium, passes to the left ventricle, and is then pumped out to the body. Choice B is incorrect because it incorrectly lists the left atrium twice. Choice C is incorrect as it rearranges the order of the chambers. Choice D is incorrect as it mistakenly switches the atria and ventricles in their positions.

5. What determines the magnitude of the frictional force acting on a book sliding across a table?

• A. Only the mass of the book
• B. Only the normal force from the table
• C. Both the mass of the book and the normal force from the table
• D. Neither the mass of the book nor the normal force from the table

Correct answer: C

Rationale: The magnitude of the frictional force acting on the book sliding across a table is determined by both the mass of the book and the normal force from the table. Frictional force is proportional to the normal force (which is influenced by the weight of the book, i.e., its mass) and is affected by the surfaces in contact and other friction-related factors. Therefore, both the mass of the book and the normal force from the table are essential in determining the frictional force experienced by the book during its sliding motion. Choices A, B, and D are incorrect because friction is a result of the interaction between the surfaces and is influenced by both the mass of the object and the normal force acting on it.

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