Input: Article: 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.

Now answer this question: The method of coating NUVs less efficient than what other LEDs?

Output: blue


Article: It was temporarily under the control of the Tibetan empire and Chinese from 650–680 and then under the control of the Umayyads in 710. The Samanid Empire, 819 to 999, restored Persian control of the region and enlarged the cities of Samarkand and Bukhara (both cities are today part of Uzbekistan) which became the cultural centers of Iran and the region was known as Khorasan. The Kara-Khanid Khanate conquered Transoxania (which corresponds approximately with modern-day Uzbekistan, Tajikistan, southern Kyrgyzstan and southwest Kazakhstan) and ruled between 999–1211. Their arrival in Transoxania signaled a definitive shift from Iranian to Turkic predominance in Central Asia, but gradually the Kara-khanids became assimilated into the Perso-Arab Muslim culture of the region.

Question: Who restored Persian control of the region?
Ans: The Samanid Empire,


Here is a question about this article: The instruments currently used in most classical music were largely invented before the mid-19th century (often much earlier) and codified in the 18th and 19th centuries. They consist of the instruments found in an orchestra or in a concert band, together with several other solo instruments (such as the piano, harpsichord, and organ). The symphony orchestra is the most widely known medium for classical music and includes members of the string, woodwind, brass, and percussion families of instruments. The concert band consists of members of the woodwind, brass, and percussion families. It generally has a larger variety and amount of woodwind and brass instruments than the orchestra but does not have a string section. However, many concert bands use a double bass. The vocal practices changed a great deal over the classical period, from the single line monophonic Gregorian chant done by monks in the Medieval period to the complex, polyphonic choral works of the Renaissance and subsequent periods, which used multiple independent vocal melodies at the same time.
What is the answer to this question: What practice has changed a great deal over the classical period?
****
So... vocal


The problem: Answer a question about this article:
UNFPA began operations in 1969 as the United Nations Fund for Population Activities (the name was changed in 1987) under the administration of the United Nations Development Fund. In 1971 it was placed under the authority of the United Nations General Assembly.
When did the organization change its name?
****
The answer: 1987


Problem: Please answer a question about the following article about Computer:
The first modern analog computer was a tide-predicting machine, invented by Sir William Thomson in 1872. The differential analyser, a mechanical analog computer designed to solve differential equations by integration using wheel-and-disc mechanisms, was conceptualized in 1876 by James Thomson, the brother of the more famous Lord Kelvin.
Who invented the first analog computer in the form of a tide-predicting machine?
A: Sir William Thomson


Question: Read this and answer the question

Grove Street Cemetery, a National Historic Landmark which lies adjacent to Yale's campus, contains the graves of Roger Sherman, Eli Whitney, Noah Webster, Josiah Willard Gibbs, Charles Goodyear and Walter Camp, among other notable burials. The cemetery is known for its grand Egyptian Revival gateway. The Union League Club of New Haven building, located on Chapel Street, is notable for not only being a historic Beaux-Arts building, but also is built on the site where Roger Sherman's home once stood; George Washington is known to have stayed at the Sherman residence while President in 1789 (one of three times Washington visited New Haven throughout his lifetime).

In what architectural style is the gateway of Grove Street Cemetery notably designed?  
Answer:
Egyptian Revival