Pyrophosphates are phosphorus oxyanions that contain two phosphorus atoms in a P-O-P linkage. A number of pyrophosphate salts exist, such as Na₂H₂P₂O₇. Often pyrophosphates are called diphosphates. The parent pyrophosphates are derived from partial or complete neutralization of pyrophosphoric acid.

Production Possibility Curve (PPC) is concave to the origin because of the increasing opportunity cost. As we move down along the PPC, to produce each additional unit of one good, more and more units of other good need to be sacrificed. That is, as we move down along the PPC, the opportunity cost increases. The curve measures the trade-off between producing one good versus another. For example, say an economy can produce 20,000 oranges and 120,000 apples. On the chart, that's point B. If it wants to produce more oranges, it must produce fewer apples.

All s orbitals are spherical in shape and have a spherical symmetry.This means that the wave function will depend on the distance from the nucleus and not on the direction.In any atom,the size of the s orbital increases as the principal quantum number of the orbital increases but its geometrical shape remains same..

Literal meaning

Physical = related to body
education = knowledge

Thus,

Physical Education is knowledge about the body. In this subject, we read about various activities which are necessary for development and growth of the body.

There are so many definitions about Physical education given by various experts.

According to Oberteuffer, <i>Physical Education is the sum of those experiences which comes to individual through movements.</i>

According to J.B.Nash, <i>Physical Education is that phase of the whole field of the education that deals with big muscle activities and their related responses.</i>

According to H.C. Buck, <i>Physical education is the part of general education programme, which is considered wit growth, development and education of children through the medium of big muscle activities. Physical activities are the tools. They are so selected and conducted as to influence every child's life physically, mentally, emotionally and morally.</i>
 

आदशो आदर्शोन्मुख यथार्थवाद स्वयं उन्हीं की गढ़ी हुई संज्ञा है। यह कहानी और उपन्यास के क्षेत्र में उनके रचनात्मक प्रयासों पर लागू होती है जो कटु यथार्थ का चित्रण करते हुए भी समस्याओं और अंतर्विरोधों को अंतत: एक आदर्शवादी और मनोवांछित समाधान तक पहुँचा देती है। सेवासदन, प्रेमाश्रम आदि उपन्यास और पंच परमेश्वर, बड़े घर की बेटी, नमक का दरोगा आदि कहानियाँ ऐसी ही हैं। बाद की रचनाओं में वे कटु यथार्थ को भी प्रस्तुत करने में किसी तरह का समझौता नहीं करते। गोदान उपन्यास और पूस की रात, कफ़न आदि कहानियाँ इसके उदाहरण हैं। साहित्य के बारे में प्रेमचंद का कहना है-

‘‘ साहित्य वह जादू की लकड़ी है जो पशुओं में ईंट-पत्थरों में पेड़-पौधों में भी विश्व की आत्मा का दर्शन करा देती है। ”

Senate: The body which had controlled Rome in the days when it was a Republic. Senate was composed of the wealthiest families of the Roman and Italian descent, mainly landowners. Senate was so powerful that emperors were judged by their behavior towards the Senate.

Q u e s t i o n : Find the number of different word that can be formed from the letter of the word intermediate such that two vowels never come together

A n s w e r is 1,51,200

The Caliphate: After Muhammad’s death in 632, there was nobody who could legitimately claim to be the next prophet of Islam. So, his political authority was transferred to the umma with no established principle of succession. This gave rise to the institution of caliphate. As per this system, the leader of the community became the deputy (khalifa) of the Prophet.

The first four caliphs (632-61)

After Muhammad’s death, many tribes broke away from the Islamic state. Some even raised their own prophets to establish communities modeled on the umma. Abu Bakr, the first caliph, suppressed the revolts by a series of campaigns. Umar, the second caliph, shaped the umma’s policy of expansion of power. It was not possible to maintain the umma out of the modest income from trade and taxes. So, the caliph and his military commanders mustered their tribal strength to conquer the lands belonging to the Byzantine Empire in the west and the Sasanian Empire in the east.

On the eve of the Arab invasions, these two empires had declined in strength due to religious conflicts and revolts by the aristocracy. In three successful campaigns (637-42), the Arabs brought Syria, Iraq, Iran and Egypt under the control of Medina. The success of the Arabs was contributed by military strategy, religious fervor and the weakness of the opposition. The third caliph, Uthman, launched further campaigns and extended the control to Central Asia. Within a decade of the death of Muhammad, the Arab-Islamic state controlled the vast territory between the Nile and the Oxus.

The Islamic Caliphate became one of the largest unitary states in history, and one of the few states to ever extend direct rule over three continents (Africa, Europe, and Asia). The Umayyads incorporated the Caucasus, Transoxiana, Sindh, the Maghreb, and the Iberian Peninsula (Al-Andalus) into the Muslim world. Historically, the caliphates were polities based on Islam which developed into multi-ethnic trans-national empires. During the medieval period, three major caliphates succeeded each other: the Rashidun Caliphate (632–661), the Umayyad Caliphate (661–750), the Abbasid Caliphate (750–1258).

Difference Between Physical Geography and Human Geography

• Rutherford  postulated  that  the  atom  must  contain  large  empty  spaces  as  most  of  the  α-particles passed through it without getting deflected. Some α-particles were deflected by the foil through small angles, while some were deflected through very large angles. Thus, Rutherford concluded that the positively charged particles in an atom must be concentrated in a very small space.
• Rutherford's Atomic Model:

Based on the results of the α-particle scattering experiments, Rutherford put forth his atomic model. An  atom  contains  a  positively  charged  centre  called the nucleus  of  the  atom.  Almost  all  the  mass  of the atom is concentrated in the nucleus. The electrons of the atom revolve around the nucleus in fixed, circular orbits. The  size  of  the  nucleus  is  many  times  smaller  than  the  size  of  the  atom.  The  nucleus  of  an  atom  is 10,000 times smaller than the atom.

उपभोग, उत्पादन एवं वितरण ये तीन अर्थशास्त्र के मुख्य घटक हैं

उपभोग (consumption) : उपभोग एक क्रिया है जिसके अंतर्गत हम अपनी आवश्यकताओं की प्रत्यक्ष संतुष्टि के लिए वस्तुओं एवं सेवाओं के उपयोगिता मूल्य का प्रयोग करते है | 

जैसे - 

वस्तुओं का उपभोग (The consumption of Articles) : भोजन लेना, चाय पीना, दूध पीना, कपडे पहना, जूते पहनना, कार चलाना, पुस्तकें पढ़ना आदि वस्तुओं का उपभोग है | 

सेवाओं का उपभोग (The consumption of services): डॉक्टर से ईलाज करवाना, दरजी से कपडे सिलवाना, मोची से जूते पॉलिश करवाना, शिक्षक से शिक्षा लेना, वकील से केस लड़वाना आदि सेवाओं का उपभोग है | 

उत्पादन (Production) : वह प्रक्रिया जिसके द्वारा कच्चे माल को उपयोगी वस्तुओं में परिवर्तित कर उपभोग लायक बनाया जाता है ताकि वस्तु की उपयोगिता तथा सेवाओं में वृद्धि की जा सके, उत्पादन कहलाता है | 

जैसे- गेंहु एवं चीनी जैसे कच्चे माल के उपयोग से बिस्कुट बनना एक उत्पादन क्रिया है | मेडिकल कॉलेज द्वारा छात्रों को डॉक्टर बनाना, लॉ कॉलेज द्वारा छात्रों को वकील बनाना आदि सेवा क्षेत्र में उत्पादन के उदाहरण हैं | 

वितरण (Distribution): वितरण एक क्रिया है जिसमें उत्पादन के कारकों जैसे - भूमि, श्रम, पूँजी एवं उद्यम के बीच आय का सही प्रकार से वितरण, ताकि अधिक से अधिक लाभ अर्जित किया जा सके | यह एक अध्ययन का विषय है जिसे वितरण का सिद्धांत कहा जाता है | 

Mourad was a poor Armenian boy. He was a cousin of Aram. Both of them belonged to the family of Garoghlanians. Mourad was proud of his family and its great and glorious traditions. For the last eleven centuries his tribe had been famous for its integrity and honesty. Mourad’s family was poverty-stricken. Sometimes it was even difficult for the members of their family to buy food for them. But nothing could shake their honesty and integrity.

Mourad was a dashing and bold young man. In this way, he resembled uncle Khosrove. Actually, he was considered to be the natural descendant of the ‘crazy streak’ in the family. Mourad was determined to achieve results. Once made a decision, he never wavered or hesitated in the middle.

Mourad had a passion for riding. He had ‘a way with a horse’. Even horses understood him. He would kick his heels into the horse’s muscles and shout: “Vazire run”. The horse would burst into a fury of speed. In this matter he was far ahead of Aram who was rather a bad rider.

Mourad loved his cousin Aram. He would come to invite him to ride. He knew Aram’s passion for riding. He would let him ride alone. He always cooperated with him and valued his advice.

In the end, Mourad was conscience-stricken. He didn’t want to bring a bad name to the family of Garoghlanians. Therefore, he and Aram decided to return the horse to its rightful owner John Byro.