Nursing Elites

1. What property of a wave remains unchanged when it passes from one medium to another with the same speed?

• A. Frequency
• B. Wavelength
• C. Amplitude
• D. Speed

Correct answer: A

Rationale: When a wave passes from one medium to another with the same speed, its frequency remains unchanged. Frequency is a characteristic of the source of the wave and does not depend on the medium through which the wave is traveling. Wavelength and speed of the wave can change when passing from one medium to another, but frequency remains constant. This is because the frequency of a wave is determined by the source that produces it, and as long as the speed remains constant, the frequency will not be altered. Amplitude, on the other hand, can change based on factors like energy loss or gain, but it is not a property that remains constant when a wave moves between different mediums with the same speed. Speed, although important for the wave's propagation, is not the property that remains unchanged when the wave transitions between mediums with the same speed. Therefore, the correct answer is frequency.

2. What causes dandruff?

• A. Excessive sebum production (This can contribute to oily dandruff)
• B. Bacterial infection (This can cause scalp folliculitis, not dandruff)
• C. Overgrowth of a specific type of fungus on the scalp
• D. Lack of proper skin hydration

Correct answer: C

Rationale: Dandruff is primarily caused by an overgrowth of a specific type of fungus called Malassezia on the scalp. This fungus feeds on the natural oils produced by the hair follicles, leading to irritation and flaking of the scalp skin. Choice A is incorrect because excessive sebum production can contribute to oily dandruff, but it is not the primary cause of dandruff. Choice B is incorrect as bacterial infection primarily causes scalp folliculitis, not dandruff. Choice D is incorrect as dandruff is not primarily caused by a lack of proper skin hydration.

3. The control center of the cell, containing genetic information (DNA), is the:

• A. Golgi apparatus
• B. Ribosome
• C. Nucleus
• D. Endoplasmic reticulum

Correct answer: C

Rationale: The correct answer is C, the nucleus. The nucleus is the control center of the cell and houses the genetic information in the form of DNA. The Golgi apparatus (choice A) is responsible for packaging and processing proteins, the ribosome (choice B) is involved in protein synthesis, and the endoplasmic reticulum (choice D) is involved in protein and lipid synthesis. Therefore, choices A, B, and D are not the correct answers as they do not house the genetic information or serve as the control center of the cell.

4. Where is fat primarily digested, and where is protein primarily digested?

• A. Mouth; stomach
• B. Stomach; small intestine
• C. Small intestine; small intestine
• D. Small intestine; stomach

Correct answer: B

Rationale: The correct answer is B. Fats are primarily digested in the small intestine, where bile from the liver emulsifies fats for enzymatic digestion. The small intestine is where most of the absorption of nutrients occurs. Proteins, on the other hand, are mainly digested in the stomach by the enzyme pepsin under acidic conditions. The stomach's acidic environment helps denature proteins, making them more accessible to pepsin for digestion. Choices A, C, and D are incorrect because they do not accurately reflect the primary sites of fat and protein digestion in the human digestive system.

5. What is the difference between a pure substance and a mixture?

• A. Pure substances have a fixed composition, mixtures don't.
• B. Mixtures have a fixed composition, pure substances don't.
• C. Pure substances can be in any state, mixtures are not always solids.
• D. Pure substances are always elements, mixtures are always compounds.

Correct answer: A

Rationale: Pure substances have a definite and constant composition, meaning they are made up of only one type of atom or molecule with fixed proportions. This composition does not vary. On the other hand, mixtures are composed of two or more substances physically combined. The components of a mixture can be present in varying proportions, leading to a variable composition. Choice A is correct as it accurately distinguishes between pure substances and mixtures based on the fixed composition of pure substances and the variable composition of mixtures. Choice B is incorrect because mixtures, not pure substances, have variable compositions. Choice C is incorrect as both pure substances and mixtures can exist in different states. Choice D is incorrect because pure substances can be compounds as well, not exclusively elements, and mixtures can contain elements and compounds.

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