Problem: White LEDs can also be made by coating near-ultraviolet (NUV) LEDs with a mixture of high-efficiency europium-based phosphors that emit red and blue, plus copper and aluminium-doped zinc sulfide (ZnS:Cu, Al) that emits green. This is a method analogous to the way fluorescent lamps work. This method is less efficient than blue LEDs with YAG:Ce phosphor, as the Stokes shift is larger, so more energy is converted to heat, but yields light with better spectral characteristics, which render color better. Due to the higher radiative output of the ultraviolet LEDs than of the blue ones, both methods offer comparable brightness. A concern is that UV light may leak from a malfunctioning light source and cause harm to human eyes or skin.
The method of coating NUVs less efficient than what other LEDs?
The answer is the following: blue

Problem: In 1941, Reza Shah was forced to abdicate in favor of his son, Mohammad Reza Pahlavi, and established the Persian Corridor, a massive supply route that would last until the end of the ongoing war. The presence of so many foreign troops in the nation also culminated in the Soviet-backed establishment of two puppet regimes in the nation; the Azerbaijan People's Government, and the Republic of Mahabad. As the Soviet Union refused to relinquish the occupied Iranian territory, the Iran crisis of 1946 was followed, which particularly resulted in the dissolution of both puppet states, and the withdrawal of the Soviets.
Who backed two puppet regimes in/around Iran during WWII?
The answer is the following: the Soviet Union

Problem: In the 1500s, Paracelsus was probably the first to criticize Galen publicly. Also in the 16th century, scientist and artist Leonardo da Vinci compared metabolism to a burning candle. Leonardo did not publish his works on this subject, but he was not afraid of thinking for himself and he definitely disagreed with Galen. Ultimately, 16th century works of Andreas Vesalius, sometimes called the father of modern medicine, overturned Galen's ideas. He was followed by piercing thought amalgamated with the era's mysticism and religion sometimes fueled by the mechanics of Newton and Galileo. Jan Baptist van Helmont, who discovered several gases such as carbon dioxide, performed the first quantitative experiment. Robert Boyle advanced chemistry. Sanctorius measured body weight. Physician Herman Boerhaave modeled the digestive process. Physiologist Albrecht von Haller worked out the difference between nerves and muscles.
Which well known gas did Jan Baptist van Helmont discover?
The answer is the following: carbon dioxide

Problem: An early advantage of AC is that the power-wasting resistors used in DC locomotives for speed control were not needed in an AC locomotive: multiple taps on the transformer can supply a range of voltages. Separate low-voltage transformer windings supply lighting and the motors driving auxiliary machinery. More recently, the development of very high power semiconductors has caused the classic "universal" AC/DC motor to be largely replaced with the three-phase induction motor fed by a variable frequency drive, a special inverter that varies both frequency and voltage to control motor speed. These drives can run equally well on DC or AC of any frequency, and many modern electric locomotives are designed to handle different supply voltages and frequencies to simplify cross-border operation.
How can different range of voltages be supplied for AC locomotives?
The answer is the following:
multiple taps on the transformer