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​​Why Surgical Lamps don’t cast shadows? Surgery lamps, also known as surgical lights or operating lights, are designed to provide high-intensity, focused lighting for surgeons during medical procedures. One of the key features of these lamps is that they are designed to minimize shadows.There are several reasons why surgery lamps are able to reduce or eliminate shadows, Multiple light sources: Surgery lamps often have multiple light sources, typically in the form of LEDs or halogen bulbs, that are arranged in a specific pattern. This allows the light to come from multiple angles, reducing the likelihood of shadows. Diffusion: Some surgery lamps use a diffuser, which is a translucent or semi-transparent material that scatters the light in different directions. This helps to soften the light and reduce shadows. Polarization: Some surgery lamps use polarized light, which can help to reduce glare and shadows. Polarized light is filtered to only allow light waves of a certain orientation to pass through, which can help to reduce reflections and shadows. Beam shaping: Surgery lamps often have a beam-shaping system that allows the light to be focused and directed precisely where it is needed. This can help to reduce shadows by ensuring that the light is only illuminating the area of interest. Shadow-reducing optics: Some surgery lamps use specialized optics, such as aspheric lenses or Fresnel lenses, that are designed to reduce shadows. These optics can help to bend and shape the light in ways that minimize shadows. Overall, the combination of multiple light sources, diffusion, polarization, beam shaping, and shadow-reducing optics all work together to help minimize shadows in surgery lamps.

​​Why are Printed Circuit Boards usually green in colour? A ‘green’ printed circuit board is not actually green all the way through. The only green part is the outer covering of resin called the solder mask or solder resist/oil. This is a hardened resin with colored pigments that is applied to the boards in a silkscreen fashion. The purpose of solder mask is to protect the electronic traces underneath from moisture and dust and to control the flow of molten solder. The actual core of a typical FR-4 circuit board is a plain, dull, yellow color, but the solder mask can come in many colors such as blue, red, yellow, black and white. Even more exotic colors can be found for the extravagant such as orange, pink, purple, matte versions and even mixed color boards. So, the question remains, why green? Green can relieve visual fatigue and aid in inspections. Other colors may not provide sufficient contrast for component visibility. Some colors can interfere with automated optical inspection (AOI) systems. - High-frequency or high-power PCBs might use different colors (e.g., red or blue) for better thermal dissipation. - Specialty PCBs, like those for medical or aerospace applications, may use unique colors. The green color has become an industry standard, but advancements in materials and designs may lead to more varied color options.

What is the difference between cold-blooded and warm-blooded? ​​The main difference between warm-blooded (endothermic) and cold-blooded (ectothermic) animals lies in their ability to regulate body temperature: Warm-blooded (Endothermic) Animals: -Maintain constant body temperature: Regardless of environmental temperature. -Generate heat internally: Through metabolic processes, like cellular respiration. -Sweat to cool down: To regulate temperature when it gets too high. Examples: Mammals (humans, dogs, bears), birds, and some fish (like sharks). Cold-blooded (Ectothermic) Animals: -Body temperature varies with environment: They absorb heat from their surroundings. -Rely on external heat sources: Like sunlight, water, or air temperature. -Bask to warm up: Expose themselves to heat sources to increase body temperature. Examples: Reptiles (snakes, lizards, turtles), amphibians (frogs, toads), fish (most species), and insects. Key differences: - Thermoregulation: Warm-blooded animals control their temperature internally, while cold-blooded animals rely on external sources. - Metabolism: Warm-blooded animals have a faster metabolism to generate heat, while cold-blooded animals have a slower metabolism. - Activity levels: Warm-blooded animals can maintain activity levels regardless of temperature, while cold-blooded animals are often more active in warmer temperatures.

How fast was the meteor that killed the dinosaurs? Scientists calculate that it was blasted into Earth by a 10-kilometer-wide asteroid or comet traveling 30 kilometers per second -- 150 times faster than a jet airliner. Scientists have concluded that the impact that created this crater occurred 65 million years ago. @TodayILearn

​​​​What is Cabin Pressure and Why do we need to maintain it in Aeroplane? Earth's atmospheric pressure varies with altitude. At the Earth's surface(sea level) , It is measured at 14.7 pounds per square inch(P.S.I) - which human beings are accustomed to because it provides the optimum amount of Oxygen. As Aeroplane ascends to higher altitudes, the atmospheric pressure decreases. There isn't oxygen to breathe and humans cannot survive more than a minute at such altitudes.In order to prevent this from happening , Cabin Pressure is maintained at appropriate levels. To maintain the pressure in the cabin equal to that at low altitude, even while the airplane is at 30,000 feet, the incoming air is held within the cabin by opening and closing an outflow valve, which releases the incoming air at a rate regulated by pressure sensors. Think of a pressurized cabin as a balloon that has a leak but is being inflated continuously. @TodayILearn

What height to reach terminal velocity? A falling person will reach terminal velocity after about 12 seconds, falling some 450 m (about 1,500 ft) in that time. That person will not then fall any faster, so it makes no difference what distance they fall if it is more than 1,500 ft - they will still reach the ground at the same speed. @TodayILearn

How many Sudoku puzzles are there? There are a total of 6,670,903,752,021,072,936,960 possible solutions, yet when mathematicians took away rotations, reflections, permutations and relabeling, which takes away the same puzzle in just a different form, the number of solutions was 5,472,730,538. @TodayILearn

What gas is released when you crack your knuckles? The fluid contains the gases oxygen, nitrogen, and carbon dioxide. When you pop or crack a joint, you stretch the joint capsule. Gas is rapidly released, which forms bubbles. In order to crack the same knuckle again, you have to wait until the gases return to the synovial fluid.

​​What is Narco Test? A person is able to lie by using his imagination. In the Narco Analysis Test, the subject's imagination is neutralised by making him semi-conscious. In this state, it becomes difficult for him to lie and his answers would be restricted to facts he is already aware of. Experts inject the subject with Sodium Pentothal or Sodium Amytal. The dose is dependent on the person's sex, age, health and physical condition. A wrong dose can result in a person going into a coma, or even death. The subject is not in a position to speak up on his own but can answer specific but simple questions. The answers are believed to be spontaneous as a semi-conscious person is unable to manipulate the answers. Sodium pentothal, or sodium thiopental, is a fast-acting, short-duration anaesthetic used in larger doses to sedate patients during surgery. It belongs to the barbiturate class of drugs that act on the central nervous system as depressants. Because the drug is believed to weaken the subject’s resolve to lie, it is sometimes referred to as a “truth serum” and is said to have been used by intelligence operatives during World War II. @TodayILearn

How long is human gestation from conception? The average length of human gestation is 280 days, or 40 weeks, from the first day of the woman's last menstrual period. The medical term for the due date is estimated date of confinement (EDC). However, only about four per cent of women actually give birth on their EDC @TodayILearn