QUES: The sky is usually clear above the desert and the sunshine duration is extremely high everywhere in the Sahara. Most of the desert enjoys more than 3,600 h of bright sunshine annually or over 82% of the time and a wide area in the eastern part experiences in excess of 4,000 h of bright sunshine a year or over 91% of the time, and the highest values are very close to the theoretical maximum value. A value of 4,300 h or 98% of the time would be recorded in Upper Egypt (Aswan, Luxor) and in the Nubian Desert (Wadi Halfa). The annual average direct solar irradiation is around 2,800 kWh/(m2 year) in the Great Desert. The Sahara has a huge potential for solar energy production. The constantly high position of the sun, the extremely low relative humidity, the lack of vegetation and rainfall make the Great Desert the hottest continuously large area worldwide and certainly the hottest place on Earth during summertime in some spots. The average high temperature exceeds 38 °C (100.4 °F) - 40 °C (104 °F) during the hottest month nearly everywhere in the desert except at very high mountainous areas. The highest officially recorded average high temperature was 47 °C (116.6 °F) in a remote desert town in the Algerian Desert called Bou Bernous with an elevation of 378 meters above sea level. It's the world's highest recorded average high temperature and only Death Valley, California rivals it. Other hot spots in Algeria such as Adrar, Timimoun, In Salah, Ouallene, Aoulef, Reggane with an elevation between 200 and 400 meters above sea level get slightly lower summer average highs around 46 °C (114.8 °F) during the hottest months of the year. Salah, well known in Algeria for its extreme heat, has an average high temperature of 43.8 °C (110.8 °F), 46.4 °C (115.5 °F), 45.5 (113.9 °F). Furthermore, 41.9 °C (107.4 °F) in June, July, August and September. In fact, there are even hotter spots in the Sahara, but they are located in extremely remote areas, especially in the Azalai, lying in northern Mali. The major part of the desert experiences around 3 – 5 months when the average high strictly exceeds 40 °C (104 °F). The southern central part of the desert experiences up to 6 – 7 months when the average high temperature strictly exceeds 40 °C (104 °F) which shows the constancy and the length of the really hot season in the Sahara. Some examples of this are Bilma, Niger and Faya-Largeau, Chad. The annual average daily temperature exceeds 20 °C (68 °F) everywhere and can approach 30 °C (86 °F) in the hottest regions year-round. However, most of the desert has a value in excess of 25 °C (77 °F). The sand and ground temperatures are even more extreme. During daytime, the sand temperature is extremely high as it can easily reach 80 °C (176 °F) or more. A sand temperature of 83.5 °C (182.3 °F) has been recorded in Port Sudan. Ground temperatures of 72 °C (161.6 °F) have been recorded in the Adrar of Mauritania and a value of 75 °C (167 °F) has been measured in Borkou, northern Chad. Due to lack of cloud cover and very low humidity, the desert usually features high diurnal temperature variations between days and nights. However, it's a myth that the nights are cold after extremely hot days in the Sahara. The average diurnal temperature range is typically between 13 °C (55.4 °F) and 20 °C (68 °F). The lowest values are found along the coastal regions due to high humidity and are often even lower than 10 °C (50 °F), while the highest values are found in inland desert areas where the humidity is the lowest, mainly in the southern Sahara. Still, it's true that winter nights can be cold as it can drop to the freezing point and even below, especially in high-elevation areas.
What is the temperature of the sand during the night?

ANS: unanswerable

QUES: Before Prince Albert's death, the palace was frequently the scene of musical entertainments, and the greatest contemporary musicians entertained at Buckingham Palace. The composer Felix Mendelssohn is known to have played there on three occasions. Johann Strauss II and his orchestra played there when in England. Strauss's "Alice Polka" was first performed at the palace in 1849 in honour of the queen's daughter, Princess Alice. Under Victoria, Buckingham Palace was frequently the scene of lavish costume balls, in addition to the usual royal ceremonies, investitures and presentations.
What type of balls did Queen Victoria avoid?

ANS: unanswerable

QUES: This reaction is favored at low pressures but is nonetheless conducted at high pressures (2.0  MPa, 20 atm or 600 inHg). This is because high-pressure H
2 is the most marketable product and Pressure Swing Adsorption (PSA) purification systems work better at higher pressures. The product mixture is known as "synthesis gas" because it is often used directly for the production of methanol and related compounds. Hydrocarbons other than methane can be used to produce synthesis gas with varying product ratios. One of the many complications to this highly optimized technology is the formation of coke or carbon:
What is synthesis gas used for?

ANS: production of methanol

QUES: In Central Africa, Ndembu warriors rub themselves with red paint during celebrations. Since their culture sees the color as a symbol of life and health, sick people are also painted with it. Like most Central African cultures, the Ndembu see red as ambivalent, better than black but not as good as white. In other parts of Africa, however, red is a color of mourning, representing death. Because red bears are associated with death in many parts of Africa, the Red Cross has changed its colors to green and white in parts of the continent.
What color are sick people painted with in Africa?

ANS:
unanswerable