romikgosai/squad_modified_2 huggingface dataset:
The structure of QD-LEDs used for the electrical-excitation scheme is similar to basic design of OLEDs. A layer of quantum dots is sandwiched between layers of electron-transporting and hole-transporting materials. An applied electric field causes electrons and holes to move into the quantum dot layer and recombine forming an exciton that excites a QD. This scheme is commonly studied for quantum dot display. The tunability of emission wavelengths and narrow bandwidth is also beneficial as excitation sources for fluorescence imaging. Fluorescence near-field scanning optical microscopy (NSOM) utilizing an integrated QD-LED has been demonstrated.

Q1: What is one scheme of Quantum Dot excitation?
A1: electrical-excitation
Q2: What is one material used in electrical-excitation?
A2: hole-transporting materials
Q3: During the electrical-excitation scheme, what moves into the quantum dot layer?
A3: electrons and holes
Q4: A Quantum Dot LED has been used in what?
A4: near-field scanning optical microscopy (NSOM)
High-power LEDs (HP-LEDs) or high-output LEDs (HO-LEDs) can be driven at currents from hundreds of mA to more than an ampere, compared with the tens of mA for other LEDs. Some can emit over a thousand lumens. LED power densities up to 300 W/cm2 have been achieved. Since overheating is destructive, the HP-LEDs must be mounted on a heat sink to allow for heat dissipation. If the heat from a HP-LED is not removed, the device will fail in seconds. One HP-LED can often replace an incandescent bulb in a flashlight, or be set in an array to form a powerful LED lamp.

Q1: How many lumens can some high-power LEDs emit?
A1: over a thousand
Q2: Up to how many densities have been achieved with LED power?
A2: 300 W/cm2
Q3: Why must High-power LEDs be mounted on a heat sink?
A3: to allow for heat dissipation
Q4: What will happen if the heat from a high-power LED is not removed?
A4: the device will fail in seconds
Q5: What can one high-power LED replace?
A5: incandescent bulb in a flashlight
LEDs have been developed by Seoul Semiconductor that can operate on AC power without the need for a DC converter. For each half-cycle, part of the LED emits light and part is dark, and this is reversed during the next half-cycle. The efficacy of this type of HP-LED is typically 40 lm/W. A large number of LED elements in series may be able to operate directly from line voltage. In 2009, Seoul Semiconductor released a high DC voltage LED, named as 'Acrich MJT', capable of being driven from AC power with a simple controlling circuit. The low-power dissipation of these LEDs affords them more flexibility than the original AC LED design.

Q1: What company has developed LEDs that can operate on AC power?
A1: Seoul Semiconductor
Q2: What is the efficacy of an AC powered HP-LED?
A2: 40 lm/W
Q3: When did Seoul Semiconductor release the first high DC voltage LED?
A3: 2009
Q4: What is so good about ac powered HP-LEDs?
A4: more flexibility
Q5: What did Seoul Semiconductor name their ac powered HP-LED?
A5: Acrich MJT
Alphanumeric LEDs are available in seven-segment, starburst and dot-matrix format. Seven-segment displays handle all numbers and a limited set of letters. Starburst displays can display all letters. Dot-matrix displays typically use 5x7 pixels per character. Seven-segment LED displays were in widespread use in the 1970s and 1980s, but rising use of liquid crystal displays, with their lower power needs and greater display flexibility, has reduced the popularity of numeric and alphanumeric LED displays.

Q1: What type of LEDs are available in seven-segment format?
A1: Alphanumeric
Q2: What is another format that Alphanumeric LEDs are available in?
A2: dot-matrix
Q3: Which alphanumeric LED display can display all letters?
A3: Starburst
Q4: What type of pixels does a dot matrix display use?
A4: 5x7
Q5: What has reduced the popularity of numeric LED displays?
A5: liquid crystal displays
Digital-RGB LEDs are RGB LEDs that contain their own "smart" control electronics. In addition to power and ground, these provide connections for data-in, data-out, and sometimes a clock or strobe signal. These are connected in a daisy chain, with the data in of the first LED sourced by a microprocessor, which can control the brightness and color of each LED independently of the others. They are used where a combination of maximum control and minimum visible electronics are needed such as strings for Christmas and LED matrices. Some even have refresh rates in the kHz range, allowing for basic video applications.

Q1: What makes RGB LEDs different?
A1: contain their own "smart" control electronics
Q2: How are Digital-RGB LED strobe signals connected?
A2: in a daisy chain
Q3: What object sources the data in of the first LED of a digital rgb LED?
A3: microprocessor
Q4: The microprocessor does what in a digital RGB LED?
A4: control the brightness and color of each LED independently of the others
Q5: What is one example of where Digital RGB LED lights are used?
A5: Christmas
An LED filament consists of multiple LED dice connected in series on a common longitudinal substrate that form a thin rod reminiscent of a traditional incandescent filament. These are being used as a low cost decorative alternative for traditional light bulbs that are being phased out in many countries. The filaments require a rather high voltage to light to nominal brightness, allowing them to work efficiently and simply with mains voltages. Often a simple rectifier and capacitive current limiting are employed to create a low-cost replacement for a traditional light bulb without the complexity of creating a low voltage, high current converter which is required by single die LEDs. Usually they are packaged in a sealed enclosure with a shape similar to lamps they were designed to replace (e.g. a bulb), and filled with inert nitrogen or carbon dioxide gas to remove heat efficiently.

Q1: What does an LED filament consist of?
A1: multiple LED dice
Q2: How are LED filaments used?
A2: a low cost decorative alternative for traditional light bulbs
Q3: What type of voltage is needed for LED filaments?
A3: high
Q4: What helps LED filaments remain low cost?
A4: a simple rectifier
Q5: Single die LEDs require what?
A5: high current converter
The current–voltage characteristic of an LED is similar to other diodes, in that the current is dependent exponentially on the voltage (see Shockley diode equation). This means that a small change in voltage can cause a large change in current. If the applied voltage exceeds the LED's forward voltage drop by a small amount, the current rating may be exceeded by a large amount, potentially damaging or destroying the LED. The typical solution is to use constant-current power supplies to keep the current below the LED's maximum current rating. Since most common power sources (batteries, mains) are constant-voltage sources, most LED fixtures must include a power converter, at least a current-limiting resistor. However, the high resistance of three-volt coin cells combined with the high differential resistance of nitride-based LEDs makes it possible to power such an LED from such a coin cell without an external resistor.

Q1: How are LEDs similar to other diodes?
A1: the current is dependent exponentially on the voltage
Q2: What is a solution to preventing an LED failure?
A2: use constant-current power supplies
Q3: What can cause a large change in current in LEDs?
A3: a small change in voltage
Q4: What is a constant-voltage source?
A4: batteries
Q5: What feature do most LED fixtures need to have?
A5: a power converter
The vast majority of devices containing LEDs are "safe under all conditions of normal use", and so are classified as "Class 1 LED product"/"LED Klasse 1". At present, only a few LEDs—extremely bright LEDs that also have a tightly focused viewing angle of 8° or less—could, in theory, cause temporary blindness, and so are classified as "Class 2". The opinion of the French Agency for Food, Environmental and Occupational Health & Safety (ANSES) of 2010, on the health issues concerning LEDs, suggested banning public use of lamps which were in the moderate Risk Group 2, especially those with a high blue component in places frequented by children. In general, laser safety regulations—and the "Class 1", "Class 2", etc. system—also apply to LEDs.

Q1: How are most LEDs classified?
A1: Class 1 LED product
Q2: What does being a Class 1 LED product mean?
A2: safe under all conditions of normal use
Q3: What type of LED can possibly cause blindness?
A3: extremely bright LEDs
Q4: Which government advocated the banning of Class 2 LEDs?
A4: French
Q5: What class are extremely bright LEDs listed as?
A5: Class 2
While LEDs have the advantage over fluorescent lamps that they do not contain mercury, they may contain other hazardous metals such as lead and arsenic. Regarding the toxicity of LEDs when treated as waste, a study published in 2011 stated: "According to federal standards, LEDs are not hazardous except for low-intensity red LEDs, which leached Pb [lead] at levels exceeding regulatory limits (186 mg/L; regulatory limit: 5). However, according to California regulations, excessive levels of copper (up to 3892 mg/kg; limit: 2500), lead (up to 8103 mg/kg; limit: 1000), nickel (up to 4797 mg/kg; limit: 2000), or silver (up to 721 mg/kg; limit: 500) render all except low-intensity yellow LEDs hazardous."

Q1: What dangerous metal can LEDs contain?
A1: arsenic
Q2: What substance does fluorescent lamps contain?
A2: mercury
Q3: Which LEDs are considered dangerous by a 2011 study?
A3: low-intensity red
Q4: According to a California study, what harmful metal is in most LEDs?
A4: lead
Q5: What LEDs are considered safer than any other?
A5: low-intensity yellow LEDs
One-color light is well suited for traffic lights and signals, exit signs, emergency vehicle lighting, ships' navigation lights or lanterns (chromacity and luminance standards being set under the Convention on the International Regulations for Preventing Collisions at Sea 1972, Annex I and the CIE) and LED-based Christmas lights. In cold climates, LED traffic lights may remain snow-covered. Red or yellow LEDs are used in indicator and alphanumeric displays in environments where night vision must be retained: aircraft cockpits, submarine and ship bridges, astronomy observatories, and in the field, e.g. night time animal watching and military field use.

Q1: What type of light is ideal for traffic signals?
A1: One-color light
Q2: In what year were luminescence standards set?
A2: 1972
Q3: What color LEDs are used when night vision is important?
A3: Red or yellow
Q4: What is an example of a night vision needed area?
A4: astronomy observatories
Q5: What is another use for one-color light?
A5: exit signs
Because of their long life, fast switching times, and their ability to be seen in broad daylight due to their high output and focus, LEDs have been used in brake lights for cars' high-mounted brake lights, trucks, and buses, and in turn signals for some time, but many vehicles now use LEDs for their rear light clusters. The use in brakes improves safety, due to a great reduction in the time needed to light fully, or faster rise time, up to 0.5 second faster[citation needed] than an incandescent bulb. This gives drivers behind more time to react. In a dual intensity circuit (rear markers and brakes) if the LEDs are not pulsed at a fast enough frequency, they can create a phantom array, where ghost images of the LED will appear if the eyes quickly scan across the array. White LED headlamps are starting to be used. Using LEDs has styling advantages because LEDs can form much thinner lights than incandescent lamps with parabolic reflectors.

Q1: Because of their high output, LED lights are very useful where?
A1: brake lights for cars
Q2: Why are LED lights sought after for various applications?
A2: their long life
Q3: LED brake lights are how many times faster than incandescent ones?
A3: 0.5 second
Q4: What color LEDs are now starting to be used more?
A4: White
Q5: What types of light can LEDs form better than incandescent?
A5: thinner
Assistive listening devices in many theaters and similar spaces use arrays of infrared LEDs to send sound to listeners' receivers. Light-emitting diodes (as well as semiconductor lasers) are used to send data over many types of fiber optic cable, from digital audio over TOSLINK cables to the very high bandwidth fiber links that form the Internet backbone. For some time, computers were commonly equipped with IrDA interfaces, which allowed them to send and receive data to nearby machines via infrared.

Q1: Where are infrared LEDs used in everday life?
A1: theaters
Q2: How are LEDs used in theaters?
A2: to send sound to listeners' receivers
Q3: LEDs can send data over what type of cable?
A3: fiber optic
Q4: What type of fiber forms the backbone of the internet?
A4: very high bandwidth
In the US, one kilowatt-hour (3.6 MJ) of electricity currently causes an average 1.34 pounds (610 g) of CO
2 emission. Assuming the average light bulb is on for 10 hours a day, a 40-watt bulb will cause 196 pounds (89 kg) of CO
2 emission per year. The 6-watt LED equivalent will only cause 30 pounds (14 kg) of CO
2 over the same time span. A building’s carbon footprint from lighting can therefore be reduced by 85% by exchanging all incandescent bulbs for new LEDs if a building previously used only incandescent bulbs.

Q1: In what country does one kilowatt-hour of electricity causes 1.34 pounds of CO 2 emission?
A1: US
Q2: How much CO2 emission would a 40-watt light bulb produce after 10 hours?
A2: 196 pounds
Q3: A 6-watt LED left on for 10 hours a day will emit how much CO 2?
A3: 30 pounds
Q4: How much can a building's carbon footprint be reduced by switching to LEDs?
A4: 85%
Machine vision systems often require bright and homogeneous illumination, so features of interest are easier to process. LEDs are often used for this purpose, and this is likely to remain one of their major uses until the price drops low enough to make signaling and illumination uses more widespread. Barcode scanners are the most common example of machine vision, and many low cost products use red LEDs instead of lasers. Optical computer mice are an example of LEDs in machine vision, as it is used to provide an even light source on the surface for the miniature camera within the mouse. LEDs constitute a nearly ideal light source for machine vision systems for several reasons:

Q1: LEDs are often used for what type of systems?
A1: Machine vision
Q2: Why are LEDs preferred for machine vision systems?
A2: so features of interest are easier to process
Q3: What can help make LEDs more widely used?
A3: price drops
Q4: What is the most common example of a machine vision system?
A4: Barcode scanners
Q5: Where are some LEDs in machine vision systems found?
A5: Optical computer mice
The light from LEDs can be modulated very quickly so they are used extensively in optical fiber and free space optics communications. This includes remote controls, such as for TVs, VCRs, and LED Computers, where infrared LEDs are often used. Opto-isolators use an LED combined with a photodiode or phototransistor to provide a signal path with electrical isolation between two circuits. This is especially useful in medical equipment where the signals from a low-voltage sensor circuit (usually battery-powered) in contact with a living organism must be electrically isolated from any possible electrical failure in a recording or monitoring device operating at potentially dangerous voltages. An optoisolator also allows information to be transferred between circuits not sharing a common ground potential.

Q1: Where are LEDs often used?
A1: free space optics communications
Q2: Where are opto-isolators found?
A2: medical equipment
Q3: What is an example of a device that uses free space optic communications?
A3: remote controls
Q4: What does an optoisolator do?
A4: allows information to be transferred between circuits not sharing a common ground potential
Q5: In what common household item can you find infrared LEDs?
A5: LED Computers
Many sensor systems rely on light as the signal source. LEDs are often ideal as a light source due to the requirements of the sensors. LEDs are used as motion sensors, for example in optical computer mice. The Nintendo Wii's sensor bar uses infrared LEDs. Pulse oximeters use them for measuring oxygen saturation. Some flatbed scanners use arrays of RGB LEDs rather than the typical cold-cathode fluorescent lamp as the light source. Having independent control of three illuminated colors allows the scanner to calibrate itself for more accurate color balance, and there is no need for warm-up. Further, its sensors only need be monochromatic, since at any one time the page being scanned is only lit by one color of light. Since LEDs can also be used as photodiodes, they can be used for both photo emission and detection. This could be used, for example, in a touchscreen that registers reflected light from a finger or stylus. Many materials and biological systems are sensitive to, or dependent on, light. Grow lights use LEDs to increase photosynthesis in plants, and bacteria and viruses can be removed from water and other substances using UV LEDs for sterilization.

Q1: What video game console uses infrared LEDs?
A1: Nintendo Wii
Q2: What device uses infrared LEDs to measure oxygen saturation?
A2: Pulse oximeters
Q3: Some flatbed scanners use what type of LED?
A3: RGB LEDs
Q4: By using LEDs, scanners do not have to what?
A4: warm-up
Q5: Grow lights use LEDs for what process?
A5: increase photosynthesis in plants
LEDs have also been used as a medium-quality voltage reference in electronic circuits. The forward voltage drop (e.g. about 1.7 V for a normal red LED) can be used instead of a Zener diode in low-voltage regulators. Red LEDs have the flattest I/V curve above the knee. Nitride-based LEDs have a fairly steep I/V curve and are useless for this purpose. Although LED forward voltage is far more current-dependent than a Zener diode, Zener diodes with breakdown voltages below 3 V are not widely available.

Q1: What quality has LEDs been used as?
A1: medium-quality
Q2: What LED has the flattest I/V curve above the knee?
A2: Red
Q3: What LEDs have a very steep I/V curve?
A3: Nitride-based LEDs
Q4: LED forward voltage is more current-dependent than what diode?
A4: Zener
Q5: Zener diodes below what voltage are not widely available?
A5: 3 V
Birds (Aves) are a group of endothermic vertebrates, characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a lightweight but strong skeleton. Birds live worldwide and range in size from the 5 cm (2 in) bee hummingbird to the 2.75 m (9 ft) ostrich. They rank as the class of tetrapods with the most living species, at approximately ten thousand, with more than half of these being passerines, sometimes known as perching birds or, less accurately, as songbirds.

Q1: What is a group of endothermic vertebrates characterised by feathers and toothless beaked jaws?
A1: Birds
Q2: What is the smallest bird?
A2: bee hummingbird
Q3: What is the largest bird?
A3: ostrich
Q4: What is the size of the smallest bird?
A4: 5 cm (2 in)
Q5: What is the size of the largest bird?
A5: 2.75 m (9 ft)
The fossil record indicates that birds are the last surviving dinosaurs, having evolved from feathered ancestors within the theropod group of saurischian dinosaurs. True birds first appeared during the Cretaceous period, around 100 million years ago. DNA-based evidence finds that birds diversified dramatically around the time of the Cretaceous–Paleogene extinction event that killed off all other dinosaurs. Birds in South America survived this event and then migrated to other parts of the world via multiple land bridges while diversifying during periods of global cooling. Primitive bird-like dinosaurs that lie outside class Aves proper, in the broader group Avialae, have been found dating back to the mid-Jurassic period. Many of these early "stem-birds", such as Archaeopteryx, were not yet capable of fully powered flight, and many retained primitive characteristics like toothy jaws in place of beaks, and long bony tails.

Q1: What are the last surviving dinosaurs, according o the fossil record?
A1: birds
Q2: When did true birds first appear?
A2: Cretaceous period
Q3: Name an example of an early stem-bird.
A3: Archaeopteryx
Birds have wings which are more or less developed depending on the species; the only known groups without wings are the extinct moas and elephant birds. Wings, which evolved from forelimbs, give most birds the ability to fly, although further speciation has led to some flightless birds, including ratites, penguins, and diverse endemic island species of birds. The digestive and respiratory systems of birds are also uniquely adapted for flight. Some bird species of aquatic environments, particularly the aforementioned flightless penguins, and also members of the duck family, have also evolved for swimming. Birds, specifically Darwin's finches, played an important part in the inception of Darwin's theory of evolution by natural selection.

Q1: What makes birds uniquely adapted for flight?
A1: digestive and respiratory systems
Q2: What type of bird particularly played an important part in the inception of Darwin's theory of evolution by natural selection?
A2: Darwin's finches
Q3: Which part of the bird developed from forelimbs?
A3: Wings
Some birds, especially corvids and parrots, are among the most intelligent animals; several bird species make and use tools, and many social species pass on knowledge across generations, which is considered a form of culture. Many species annually migrate great distances. Birds are social, communicating with visual signals, calls, and bird songs, and participating in such social behaviours as cooperative breeding and hunting, flocking, and mobbing of predators. The vast majority of bird species are socially monogamous, usually for one breeding season at a time, sometimes for years, but rarely for life. Other species have polygynous ("many females") or, rarely, polyandrous ("many males") breeding systems. Birds produce offspring by laying eggs which are fertilized through sexual reproduction. They are usually laid in a nest and incubated by the parents. Most birds have an extended period of parental care after hatching. Some birds, such as hens, lay eggs even when not fertilized, though unfertilized eggs do not produce offspring.

Q1: Which type of birds are among the most intelligent animals?
A1: corvids and parrots
Q2: How to birds produce offspring?
A2: by laying eggs which are fertilized through sexual reproduction
Q3: Where are eggs usually laid?
A3: nest
Many species of birds are economically important. Domesticated and undomesticated birds (poultry and game) are important sources of eggs, meat, and feathers. Songbirds, parrots, and other species are popular as pets. Guano (bird excrement) is harvested for use as a fertilizer. Birds prominently figure throughout human culture. About 120–130 species have become extinct due to human activity since the 17th century, and hundreds more before then. Human activity threatens about 1,200 bird species with extinction, though efforts are underway to protect them. Recreational birdwatching is an important part of the ecotourism industry.

Q1: Which birds are popular as pets?
A1: Songbirds, parrots
Q2: What is guano?
A2: bird excrement
Q3: What is the name of bird excrement?
A3: Guano
Q4: What is harvested for use as fertilizer?
A4: Guano
Q5: How many species of birds have become extinct as a result of human activity?
A5: 120–130