In the following questions, you have two passages with 5 questions in each passage. Read the passages carefully and choose the best answer to each question out of the four alternatives.

The advent of electric power was, in a way, comparable to the successful development and application of nuclear power in the 20th century. In fact, the historical roots of electricity extend far back into antiquity. Many men had a hand both in acquring basic knowledge about the invisible form of power and in developing the ways adopted for practical purpose. One of the vital keys that helped to unlock the doors leading to the production of electricity was the discovery, in 1831, of the principle of electromagnetic induction. This discovery was made simultaneously by Michael Faladay in England and Joseph Henry in the United States. From it came the generator, sometimes also called the dynamo but several decades of development had to fol low before the first practical dynamos or generator came into existence in early 1870.