Nokea
Nuclear fusion powers the sun and other stars. What is the main obstacle to achieving controlled nuclear fusion on Earth for energy production?
- A. Lack of suitable materials to handle high temperatures and pressures.
- B. Limited availability of fusion fuels like deuterium and tritium.
- C. Difficulty in containing the plasma where fusion occurs.
- D. All of the above
Correct Answer: D
Rationale: The main obstacle to achieving controlled nuclear fusion on Earth for energy production involves a combination of factors. A) Lack of suitable materials to handle high temperatures and pressures is a significant challenge due to the extreme conditions required for fusion reactions. B) Limited availability of fusion fuels like deuterium and tritium can pose a constraint on the scalability and sustainability of fusion energy. C) Difficulty in containing the plasma where fusion occurs is another critical issue as plasma instabilities and heat losses can hinder the efficiency of fusion reactions. Therefore, all of the options (A, B, and C) contribute to the challenges in achieving controlled nuclear fusion for energy production on Earth.
You may also like to solve these questions
What is the unit of measurement for density?
- A. Grams per liter (g/L)
- B. Kilograms per cubic meter (kg/m³)
- C. Pounds per square inch (psi)
- D. Newtons per meter (N/m)
Correct Answer: A
Rationale: Density is defined as mass per unit volume. The most commonly used unit for density in the metric system is grams per liter (g/L). Kilograms per cubic meter (kg/m³) is also a common unit for density, but grams per liter is more frequently used in everyday measurements. Pounds per square inch (psi) is a unit of pressure, not density. Newtons per meter (N/m) is a unit of force per unit length, not density.
What phenomenon is responsible for the mirage effect seen in deserts?
- A. Diffraction
- B. Refraction
- C. Interference
- D. Polarization
Correct Answer: B
Rationale: Refraction is the bending of light as it passes from one medium to another of different density. In deserts, the temperature gradient causes light to bend, creating the mirage effect where distant objects appear distorted or displaced. Diffraction refers to the bending of light around obstacles or apertures, not the cause of mirages. Interference involves the superposition of two or more waves, which is not the mechanism behind mirages. Polarization refers to the orientation of light waves in a specific plane and is not responsible for the mirage effect in deserts. Therefore, the correct answer is refraction.
What is the role of the pancreas in the digestive system?
- A. To store bile
- B. To secrete digestive enzymes
- C. To digest proteins
- D. To absorb nutrients
Correct Answer: B
Rationale: The correct answer is B: 'To secrete digestive enzymes.' The pancreas plays a crucial role in the digestive system by secreting digestive enzymes that aid in breaking down food in the small intestine. These enzymes help in the digestion of carbohydrates, fats, and proteins, facilitating the absorption of nutrients from the digested food. Choice A is incorrect because the pancreas is not responsible for storing bile; the gallbladder stores bile. Choice C is incorrect because the pancreas secretes enzymes for protein digestion but does not digest proteins itself. Choice D is incorrect as the absorption of nutrients primarily occurs in the small intestine, not in the pancreas.
What is the term for the involuntary muscle contractions that move food through the digestive tract?
- A. Segmentation
- B. Peristalsis
- C. Chyme
- D. Emulsification
Correct Answer: B
Rationale: Peristalsis is the correct term for the involuntary muscle contractions that move food through the digestive tract. These contractions help push food along the digestive system, facilitating digestion and absorption of nutrients. Segmentation, on the other hand, refers to the mixing and breaking down of food in the intestines, not the movement of food. Chyme is the semi-fluid mass of partially digested food in the stomach and small intestine, not the muscle contractions. Emulsification is the process of breaking down fat globules into smaller droplets to aid in digestion, not the movement of food through the digestive tract. Therefore, peristalsis is the most appropriate term for this function.
What is the term for the gradual loss of topsoil due to wind or water erosion?
- A. Desertification
- B. Leaching
- C. Salinization
- D. Acidification
Correct Answer: A
Rationale: A) Desertification is the correct term for the gradual loss of topsoil due to wind or water erosion. It refers to the process by which fertile land becomes desert, usually due to factors like drought, deforestation, or inappropriate agriculture practices. This process can lead to the degradation of land and contribute to the expansion of deserts. B) Leaching is the process in which minerals are washed out of the soil by water moving downwards through it. This is different from the loss of topsoil due to erosion. C) Salinization occurs when salt accumulates in the soil, typically as a result of irrigation in arid regions. While salinization affects soil quality, it is not specifically related to the gradual loss of topsoil due to erosion. D) Acidification refers to the decrease in soil pH, often caused by factors like acid rain or the use of acidic fertilizers. This process is distinct from the gradual loss of topsoil due to erosion.