Nokea
What happens to the frequency of a wave if its wavelength decreases while the speed remains constant?
- A. Frequency decreases
- B. Frequency increases
- C. Frequency remains constant
- D. Frequency becomes zero
Correct Answer: B
Rationale: The correct answer is B: Frequency increases. Frequency and wavelength are inversely proportional in a wave with a constant speed. When the wavelength decreases while the speed remains constant, the frequency must increase to maintain the constant speed of the wave. This relationship is governed by the equation: speed = frequency x wavelength. Choice A is incorrect as frequency increases when wavelength decreases. Choice C is incorrect as the frequency changes in this scenario. Choice D is incorrect as the frequency does not become zero but increases when the wavelength decreases.
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Which of the following is a strong acid?
- A. Acetic acid (CH₃COOH)
- B. Hydrochloric acid (HCl)
- C. Citric acid
- D. Carbonic acid (H₂CO₃)
Correct Answer: B
Rationale: Hydrochloric acid (HCl) is a strong acid because it completely ionizes in water to produce hydrogen ions, leading to a high concentration of H⺠ions in solution. This characteristic makes it a strong acid. Acetic acid (CH₃COOH), citric acid, and carbonic acid (H₂CO₃) are weak acids as they only partially ionize in water, resulting in a lower concentration of H⺠ions compared to strong acids. Therefore, hydrochloric acid is the correct choice as a strong acid.
What is the myelin sheath and what does it do?
- A. A group of nerve cells that perform a specific function.
- B. A fatty substance that insulates some nerve fibers.
- C. A fluid-filled cavity within the brain.
- D. The junction between two neurons.
Correct Answer: B
Rationale: The myelin sheath is a fatty substance that insulates some nerve fibers. It is made up of specialized cells that wrap around the axons of neurons, providing insulation and speeding up the transmission of nerve impulses. Choice A is incorrect as the myelin sheath is not a group of nerve cells but rather a substance that surrounds nerve fibers. Choice C is incorrect as the myelin sheath is not a fluid-filled cavity within the brain. Choice D is incorrect as the myelin sheath is not the junction between two neurons.
Which state of matter has particles that are highly organized in a fixed pattern and vibrate in place?
- A. Solid
- B. Liquid
- C. Gas
- D. Plasma
Correct Answer: A
Rationale: The correct answer is 'Solid.' Solids have particles that are tightly packed together in a fixed pattern, allowing them to vibrate in place. This highly organized structure gives solids a definite shape and volume. In contrast, liquids have particles that are close together but can move past each other, enabling them to flow and take the shape of their container. Gases have particles that are far apart and move freely in all directions, filling the entire space available to them. Plasmas, on the other hand, have highly energized particles that do not have a fixed pattern and are not confined by a definite volume or shape.
How much sugar is in a 1 M solution of sugar water?
- A. 1 L of water
- B. 100 mL of solution
- C. Every 100 g of water
- D. It depends on the type of sugar
Correct Answer: B
Rationale: A 1 M solution of sugar water contains 1 mole of sugar in 1 liter of solution. Since 1 M (molar) solution means there is 1 mole of solute (sugar) dissolved in 1 liter of solvent (water), the correct answer is 100 mL of solution. Choice A, '1 L of water,' is incorrect because it does not specify the total volume of the solution. Choice C, 'Every 100 g of water,' is incorrect as it focuses on the weight of water, not the volume of the solution. Choice D, 'It depends on the type of sugar,' is incorrect since the concentration of a 1 M solution is standardized and does not vary based on the type of sugar used.
Which term refers to the condition where a muscle shortens in length while generating force, leading to movement at a joint?
- A. Isometric contraction
- B. Eccentric contraction
- C. Isotonic contraction
- D. Concentric contraction
Correct Answer: D
Rationale: Concentric contraction refers to the condition where a muscle shortens in length while generating force, leading to movement at a joint. This type of contraction is commonly associated with the lifting phase of an exercise where the muscle is actively shortening against resistance. Isometric contraction (Choice A) involves muscle contraction without a change in muscle length, Eccentric contraction (Choice B) involves the muscle lengthening while generating force, and Isotonic contraction (Choice C) refers to muscle contraction against a constant load with a change in muscle length.