Nursing Elites

1. Which property of a substance refers to its ability to undergo a chemical change and form new substances?

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

Correct answer: C

Rationale: Reactivity is the property of a substance that describes its ability to undergo a chemical change and form new substances through chemical reactions. Density, mass, and volume are physical properties of a substance and do not directly relate to its ability to undergo chemical changes. Density is the mass of a substance per unit volume, mass is the amount of matter present, and volume is the amount of space occupied by the substance. Reactivity specifically deals with how likely a substance is to engage in chemical reactions. Therefore, the correct answer is C - Reactivity.

2. What are the components of an ECG?

• A. P wave, T wave, U wave
• B. P wave, QRS complex, T wave
• C. QRS complex, S wave, P wave
• D. T wave, S wave, U wave

Correct answer: B

Rationale: The correct answer is B: P wave, QRS complex, T wave. The components of an ECG include the P wave (atrial depolarization), QRS complex (ventricular depolarization), and T wave (ventricular repolarization). The P wave represents atrial depolarization, the QRS complex represents ventricular depolarization, and the T wave represents ventricular repolarization. Options A, C, and D have incorrect combinations of ECG components. Option A incorrectly includes the U wave, which is not a standard component of a typical ECG. Option C includes the S wave, which is not a primary component of a standard ECG. Option D includes the U wave, which is not a standard component, and the S wave, which is not a primary component of an ECG. Therefore, option B is the most accurate combination of components for an ECG.

3. Which type of energy is associated with the random motion of particles in a substance?

• A. Potential energy
• B. Mechanical energy
• C. Thermal energy
• D. Chemical energy

Correct answer: C

Rationale: Thermal energy is the correct answer as it is associated with the random motion of particles in a substance. When particles move randomly, they generate heat energy, which is a form of thermal energy. Potential energy is stored energy that can be converted into other forms when released, such as kinetic energy. Mechanical energy is the sum of potential and kinetic energy in an object, which is not directly related to the random motion of particles. Chemical energy is energy stored in the bonds of chemical compounds and is not specifically related to the motion of particles.

4. How does kinetic energy change when the velocity of an object is doubled?

• A. Kinetic energy is halved
• B. Kinetic energy quadruples
• C. Kinetic energy doubles
• D. Kinetic energy remains the same

Correct answer: B

Rationale: Kinetic energy is directly proportional to the square of the velocity of an object according to the kinetic energy formula (KE = 0.5 * m * v^2). When the velocity is doubled, the kinetic energy increases by a factor of 2^2 = 4. Therefore, the kinetic energy quadruples when the velocity of an object is doubled. Choice A is incorrect because halving the kinetic energy would be the result if the velocity was halved, not doubled. Choice C is incorrect because doubling the velocity would result in a fourfold increase in kinetic energy, not just a double. Choice D is incorrect because kinetic energy is directly related to the velocity of an object, so if the velocity changes, the kinetic energy changes accordingly.

5. The adrenal cortex produces a group of steroid hormones called corticosteroids. What is a MAJOR function of corticosteroids?

• A. Regulate insulin sensitivity and blood sugar levels
• B. Control blood pressure and electrolyte balance
• C. Stimulate the immune system and inflammatory response
• D. Promote growth and development during puberty

Correct answer: B

Rationale: Corticosteroids, produced by the adrenal cortex, primarily function to control blood pressure and electrolyte balance. One of the key corticosteroids, aldosterone, plays a crucial role in regulating sodium and potassium levels in the body. This regulation is essential for maintaining blood pressure and electrolyte balance. Choices A, C, and D are incorrect because corticosteroids do not primarily regulate insulin sensitivity and blood sugar levels, stimulate the immune system and inflammatory response, or promote growth and development during puberty. While corticosteroids can have effects on insulin sensitivity, immune response, and growth, their major role is in maintaining blood pressure and electrolyte balance.

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