What type of energy is stored in food?
- A. Mechanical energy
- B. Kinetic energy
- C. Chemical potential energy
- D. Thermal energy
Correct Answer: C
Rationale: Food stores energy in the form of chemical potential energy. This energy is released during digestion and metabolism to provide the body with the energy it needs to function. It is derived from the bonds within the molecules of food, such as carbohydrates, fats, and proteins. Choice A, mechanical energy, is incorrect as food does not store energy in the form of mechanical energy. Choice B, kinetic energy, is incorrect as kinetic energy is associated with the motion of objects, not stored in food. Choice D, thermal energy, is incorrect as thermal energy relates to heat energy, which is not the primary form of energy stored in food.
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Which skin condition is characterized by red, itchy, and inflamed patches?
- A. Eczema
- B. Psoriasis
- C. Melanoma
- D. Keloid
Correct Answer: A
Rationale: Eczema is a skin condition characterized by red, itchy, and inflamed patches. It is a common condition that can vary in severity and often presents with symptoms such as dry, scaly skin, and sometimes oozing or crusting. Psoriasis, on the other hand, presents with red, scaly patches but is not typically described as itchy. Melanoma is a type of skin cancer characterized by the development of abnormal moles, while keloid is a type of raised scar that can occur after an injury to the skin. Therefore, the correct answer is eczema due to its specific symptom presentation of red, itchy, and inflamed patches.
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.
Which statement accurately describes the periodic trends in atomic radius?
- A. Increases down a group and decreases across a period
- B. Decreases down a group and increases across a period
- C. Remains constant throughout the table
- D. Fluctuates unpredictably based on individual elements
Correct Answer: A
Rationale: The correct statement is that atomic radius increases down a group and decreases across a period. When moving down a group, additional electron shells increase the distance from the nucleus, leading to larger atomic radii. On the other hand, when moving across a period, the number of electron shells remains constant, but the increasing nuclear charge pulls electrons closer, resulting in smaller radii. Choice B is incorrect because atomic radius does not decrease down a group and increase across a period. Choice C is incorrect because atomic radius does not remain constant; it exhibits specific trends. Choice D is incorrect because atomic radius follows predictable trends based on the periodic table structure, rather than fluctuating unpredictably.
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.
How does the potential energy of an object change when it is compressed?
- A. Potential energy decreases
- B. Potential energy increases
- C. Potential energy remains constant
- D. Potential energy becomes zero
Correct Answer: B
Rationale: When an object is compressed, its potential energy increases. This is because work is done on the object to compress it, resulting in an increase in potential energy stored in the object as it is compressed against an opposing force. The potential energy is transformed and stored within the object due to the work done during the compression process, leading to an increase in its potential energy. Choice A is incorrect because compression involves doing work on the object, increasing its potential energy. Choice C is incorrect because compression involves a change in position and potential energy. Choice D is incorrect because compression does not reduce potential energy to zero; rather, it increases it due to the work done in compressing the object.