QUES: The energy levels of hydrogen can be calculated fairly accurately using the Bohr model of the atom, which conceptualizes the electron as "orbiting" the proton in analogy to the Earth's orbit of the Sun. However, the electromagnetic force attracts electrons and protons to one another, while planets and celestial objects are attracted to each other by gravity. Because of the discretization of angular momentum postulated in early quantum mechanics by Bohr, the electron in the Bohr model can only occupy certain allowed distances from the proton, and therefore only certain allowed energies.
What model id used to calculate energy levels of hydrogen?

ANS: Bohr model

QUES: Caesar was assassinated on March 15, 44 BC. The assassination was led by Gaius Cassius and Marcus Brutus. Most of the conspirators were senators, who had a variety of economic, political, or personal motivations for carrying out the assassination. Many were afraid that Caesar would soon resurrect the monarchy and declare himself king. Others feared loss of property or prestige as Caesar carried out his land reforms in favor of the landless classes. Virtually all the conspirators fled the city after Caesar's death in fear of retaliation. The civil war that followed destroyed what was left of the Republic.
What did some members of the conspiracy believe Caesar would bring back?

ANS: the monarchy

QUES: The American people are mostly multi-ethnic descendants of various culturally distinct immigrant groups, many of which have now developed nations. Some consider themselves multiracial, while acknowledging race as a social construct. Creolization, assimilation and integration have been continuing processes. The African-American Civil Rights Movement (1955–1968) and other social movements since the mid-twentieth century worked to achieve social justice and equal enforcement of civil rights under the constitution for all ethnicities. In the 2000s, less than 5% of the population identified as multiracial. In many instances, mixed racial ancestry is so far back in an individual's family history (for instance, before the Civil War or earlier), that it does not affect more recent ethnic and cultural identification.
When did the Hispanic Civil Rights Movement occur?

ANS: unanswerable

QUES: In the late 1980s, key breakthroughs in GaN epitaxial growth and p-type doping ushered in the modern era of GaN-based optoelectronic devices. Building upon this foundation, Dr. Moustakas at Boston University patented a method for producing high-brightness blue LEDs using a new two-step process. Two years later, in 1993, high-brightness blue LEDs were demonstrated again by Shuji Nakamura of Nichia Corporation using a gallium nitride growth process similar to Dr. Moustakas's. Both Dr. Moustakas and Mr. Nakamura were issued separate patents, which confused the issue of who was the original inventor (partly because although Dr. Moustakas invented his first, Dr. Nakamura filed first).[citation needed] This new development revolutionized LED lighting, making high-power blue light sources practical, leading to the development of technologies like BlueRay, as well as allowing the bright high resolution screens of modern tablets and phones.[citation needed]
What technology was made possible by low-power blue light sources?

ANS:
unanswerable