Nursing Elites

1. What does half-life refer to?

• A. Radioactive intensity to completely disappear
• B. The number of neutrons in a nucleus to double
• C. The number of protons in a nucleus to change
• D. An isotope to decay by half of its initial quantity

Correct answer: D

Rationale: Half-life refers to the time it takes for half of the radioactive atoms in a sample to decay. This means that after one half-life, half of the initial quantity of the radioactive substance will have decayed. Choice A is incorrect because radioactive intensity doesn't completely disappear during half-life. Choice B is incorrect as half-life doesn't refer to the number of neutrons doubling. Choice C is incorrect as half-life doesn't relate to the number of protons changing.

2. An object is initially at rest. Which of the following will definitely NOT cause it to move?

• A. A constant force acting on it
• B. No force acting on it
• C. A force that increases in magnitude over time
• D. A force that decreases in magnitude over time

Correct answer: B

Rationale: The correct answer is B because if an object is initially at rest and no force is acting on it, it will remain at rest due to Newton's First Law of Motion. This law states that an object at rest will stay at rest unless acted upon by an external force. Choices A, C, and D all involve forces acting on the object, which would cause it to move according to Newton's laws of motion. Choice A, a constant force acting on the object, would cause it to move at a constant velocity. Choice C, a force that increases in magnitude over time, would accelerate the object. Choice D, a force that decreases in magnitude over time, would decelerate the object.

3. Which property of matter refers to the amount of space occupied by an object and is measured in cubic units?

• A. Mass
• B. Density
• C. Weight
• D. Volume

Correct answer: D

Rationale: Volume is the property of matter that refers to the amount of space occupied by an object. It is measured in cubic units, such as cubic meters or cubic centimeters. Mass, on the other hand, is the amount of matter in an object, weight is the force of gravity acting on an object, and density is the mass per unit volume of a substance. In this question, the key concept is the space occupied by an object, which directly relates to volume, making it the correct answer. Choices A, B, and C are incorrect as they do not specifically pertain to the amount of space occupied by an object.

4. Which of the following structures is responsible for preventing the backflow of blood from the left ventricle into the left atrium?

• A. Aortic valve
• B. Pulmonary valve
• C. Tricuspid valve
• D. Mitral valve

Correct answer: D

Rationale: The correct answer is D, the Mitral valve. The mitral valve, also known as the bicuspid valve, is situated between the left atrium and the left ventricle. Its primary function is to prevent the backflow of blood from the left ventricle into the left atrium during ventricular contraction. The other choices are incorrect because: A) The aortic valve prevents backflow from the aorta into the left ventricle. B) The pulmonary valve prevents backflow from the pulmonary artery into the right ventricle. C) The tricuspid valve prevents backflow from the right ventricle into the right atrium.

5. Which structure in the ear is responsible for maintaining balance?

• A. Cochlea
• B. Semicircular canals
• C. Eardrum
• D. Auditory nerve

Correct answer: B

Rationale: The correct answer is the semicircular canals. These structures in the inner ear are responsible for maintaining balance and equilibrium by detecting rotational movements of the head. The cochlea is responsible for hearing as it contains the sensory cells for detecting sound vibrations, the eardrum is a membrane that transmits sound waves to the middle ear, and the auditory nerve carries sound signals from the cochlea to the brain for processing. Therefore, choices A, C, and D are incorrect as they are not primarily associated with maintaining balance.

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