Nokea
What property of a wave determines its pitch in sound waves?
- A. Amplitude
- B. Frequency
- C. Wavelength
- D. Speed
Correct Answer: B
Rationale: The pitch of a sound wave is determined by its frequency. Frequency is the number of cycles of a wave that occur in a unit of time, usually measured in hertz (Hz). Higher frequencies correspond to higher pitches, while lower frequencies correspond to lower pitches. Amplitude refers to the height of a wave and is related to the loudness of the sound. Wavelength is the distance between two consecutive points in a wave that are in phase, and speed is the rate at which a wave travels through a medium. Therefore, the correct answer is frequency as it directly correlates with the pitch of a sound wave.
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When making a dilution, what do you do?
- A. Add more solvent to a concentrated solution
- B. Change the temperature of the solution
- C. Decrease the concentration of a solution
- D. All of the above
Correct Answer: C
Rationale: When making a dilution, you decrease the concentration of a solution by adding more solvent to a concentrated solution. This process does not involve changing the temperature of the solution, so option B is incorrect. Option A is also incorrect because you are not adding more solute to the solution during dilution. Therefore, the correct answer is C) Decrease the concentration of a solution. Options A and B are incorrect as dilution involves adding more solvent, not solute, and does not require changing the temperature of the solution.
What unit is used for measuring luminous flux, which indicates the perceived brightness of a light source by the human eye?
- A. Candela
- B. Lumen
- C. Lux
- D. Hertz
Correct Answer: B
Rationale: Lumen is the correct unit for measuring luminous flux, which quantifies the total visible light emitted by a source per unit of time. Candela measures luminous intensity, lux measures illuminance, and Hertz measures frequency. Therefore, in the context of measuring the perceived brightness of a light source by the human eye, luminous flux is quantified in lumens.
What does the innate immune system provide?
- A. Nonspecific, immediate defense against pathogens
- B. Specific, long-term immune response through memory cells
- C. Both (a) and (b)
- D. Neither (a) nor (b)
Correct Answer: A
Rationale: The correct answer is A. The innate immune system provides nonspecific, immediate defense against pathogens. It is the body's first line of defense in responding to infections and does not involve memory cells or specific long-term immune responses like the adaptive immune system. Choice B is incorrect because specific, long-term immune responses through memory cells are characteristics of the adaptive immune system, not the innate immune system. Choice C is incorrect because the innate immune system does not provide specific, long-term immune responses. Choice D is incorrect because the innate immune system does provide an immediate defense against pathogens.
What property of a substance remains constant regardless of changes in its shape or size?
- A. Mass
- B. Weight
- C. Density
- D. Volume
Correct Answer: A
Rationale: Mass is a measure of the amount of matter in an object and remains constant regardless of changes in its shape or size. Weight, density, and volume can all change depending on the conditions, but mass remains the same. For example, if you have a piece of clay and you shape it into a ball or flatten it into a pancake, the amount of clay (mass) will remain the same, even though the shape and size have changed. Weight is the force acting on an object due to gravity, which can vary depending on the gravitational pull. Density is the mass per unit volume, so it changes with variations in volume. Volume is the amount of space occupied by an object, which can change if the shape or size of the object is altered.
Which type of muscle tissue has a unique branching network and is found in the heart?
- A. Skeletal muscle
- B. Cardiac muscle
- C. Smooth muscle
- D. Multifidus muscle
Correct Answer: B
Rationale: The correct answer is B, Cardiac muscle. Cardiac muscle is the type of muscle tissue that has a unique branching network and is found in the heart. This type of muscle is involuntary and contracts rhythmically to pump blood throughout the body. Skeletal muscle, choice A, is attached to bones and is responsible for voluntary movements. Smooth muscle, choice C, is found in the walls of internal organs and blood vessels, playing a role in involuntary movements. Multifidus muscle, choice D, is a specific muscle in the back that helps with spinal stability, unrelated to the unique branching network found in cardiac muscle.