Luminous flux is the measure of the total amount of visible light emitted by a light source, measured in lumens. It represents the brightness of the light emitted. On the other hand, high voltage refers to the electrical potential difference between two points in a circuit, measured in volts. High voltage is used to transmit electricity over long distances and is typically found in power lines and electrical systems. In summary, luminous flux measures the brightness of light, while high voltage measures the electrical potential difference in a circuit. **

Silk shines because of its unique structure, which includes triangular prism-like structures on the surface that refract light and give it a lustrous appearance. The molecular structure of silk also allows it to repel water, as the tightly packed protein chains create a hydrophobic surface. Additionally, silk has high strength due to the strong intermolecular forces between the protein chains, as well as its unique molecular structure that allows it to withstand tension and stretching. These properties make silk a highly desirable material for a wide range of applications, from textiles to medical devices. **

The high jump is a track and field event in which athletes must jump over a horizontal bar. The height of the bar is adjusted throughout the competition, starting at a lower height and increasing as the competition progresses. The world record for the high jump is 2.45 meters (8 feet 0.46 inches) for men and 2.09 meters (6 feet 10.28 inches) for women. **

Some windows on high-rise buildings shine brightly and cause glare because they are made of highly reflective materials such as glass or have been treated with reflective coatings. These materials are designed to allow maximum light transmission and can reflect sunlight more intensely than regular windows. Additionally, the angle of the sun and the position of the building can also contribute to certain windows appearing brighter and causing glare. Buildings with a specific orientation or design may have windows that are more prone to reflecting sunlight in a way that causes glare. **

High-voltage and extra-high-voltage power lines have high voltages instead of high currents because high voltages allow for the transmission of large amounts of power over long distances with minimal energy loss. When the voltage is increased, the current decreases, which reduces the energy lost as heat in the power lines. This is known as the inverse relationship between voltage and current, as described by Ohm's law. Therefore, by using high voltages, power companies can efficiently transmit electricity over long distances without significant energy loss. **

The correct phrase is "a high number of." This phrase is used to indicate a large quantity or amount of something. For example, "There was a high number of participants in the race." It is important to use the correct preposition "of" after "number" to convey the intended meaning. **

Self-luminous bodies are objects that emit their own light, as opposed to reflecting light from another source. Examples of self-luminous bodies include stars, the sun, and certain types of light bulbs. These objects generate their own energy through processes like nuclear fusion or electrical current, which produces light as a byproduct. **

No, the luminous clock is not radioactive. The luminescence in the clock is typically achieved using a phosphorescent material that absorbs light and then slowly releases it over time. This process does not involve any radioactive materials. The glow from the clock is simply a result of this light-absorption and emission process. **