AC or DC: The War of Currents Reading Answers

Oct 21, 2022

AC or DC The War of Currents Reading Answers 13 different types of questions. Candidates will be shown various question types with clear instructions in this IELTS Section. AC or DC The War of Currents Reading Answers comprises three types of questions: no more than two words, and choose the correct option. For no more than two words, candidates are required to answer based in relevance woth the passage and it should be within two words. To choose the correct option, candidates must read the IELTS Reading passage and understand the statement provided.

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Reading Passage Question

Electricity can be delivered in either alternating current (AC), or direct current (DC), and in the late 1880s in America, with electricity delivery in its infancy, it initially seemed clear which system was superior. Thomas Edison, a home-grown American inventor, heavily favoured DC from the start. Yet the limitations of his system would become increasingly obvious, as would the advantages of AC, and despite Edison’s best efforts, his crusade would ultimately be lost.

In 1879, Edison’s team at Menlo Park had improved the electric light bulb, but Edison needed an efficient electricity distribution system to capitalise on this. Thus, in 1880, he founded the Edison Illuminating Company and constructed a generating station providing 110 volts of direct current. Yet such a system has drawbacks. Due to the low voltage, there Hows correspondingly higher current, meaning that the electrical resistance of the transmission wires significantly reduces the voltage as it travels further afield. Whatever thickness of wire is used, there is a natural limitation in the distance over which the electricity can be economically transmitted.
There are, however, benefits to using DC. It can allow storage batteries to be directly connected to the electricity grid, giving extra power to meet sudden short-term peaks of demand, or backup during breakdown of supply. Furthermore, during Edison’s time, there were no practical AC motors, only DC ones. Also, most of the load consisted of incandescent light bulbs, which ran well on DC. Perhaps most importantly, Edison had the patents (legal rights) to many associated DC devices which he and his team had invented, such as meters, telegraphic devices, and household machinery. Thus, the widespread adoption of DC across America would see him gain considerably from patent royalties.
Still, all such inventions were somewhat useless when DC electricity could only be delivered to customers within a few kilometers of the generating source. To overcome this problem, the best answer is to transform, or step-up, the voltage to very high levels for transmission, and then transform it down to safe levels for customer use. This also allows thinner and less expensive wires, but there is no low-cost technology to transform voltage — unless one uses AC, and it was the brilliant physicist and prolific inventor, Nikola Tesla, who had extensively researched this system.
Tesla, a penniless immigrant from Serbia, worked for a year at Edison’s Menlo lab. He had actually proposed the AC system to Edison, but Edison, an empirical experimenter with little formal education, dismissed it as impractical. Tesla, with the mathematical training and formal theoretical knowledge, was able to understand AC’s potential, even inventing an AC polyphase electric induction motor. Tesla soon felt he was not being given due credit or enough financial compensation from Edison, and a direct confrontation led to him immediately resigning, after which he was reduced to working as a labourer for a few years to make ends meet.
But Tesla was not the first to advocate AC. The system was being trialed in many European countries, with considerable success. One of the converts to the cause was a university-trained electrical engineer named George Westinghouse, and he was willing to invest in the idea. He formed a company and purchased the patents to AC-based transformer technology from its European inventors, as well those to Tesla’s AC polyphase electric motor, among others. This eventually led to him hiring Tesla himself to help commercialise AC, and promote it as a better system. A bitter feud, known as the ‘War of Currents’ was set to begin.
Edison's first strike was to claim that high-voltage systems were too dangerous to use. Certainly they were dangerous, but Westinghouse countered that such risks could be minimised and were considerably outweighed by the benefits. Edison’s next strike was to use his influence on various American state governments to limit power transmission to low voltages, effectively eliminating AC from the competition. When this failed, Edison was prepared to conduct public electrocutions of animals by AC — even on a rogue elephant no longer wanted by its circus owners. In the battle of public opinion, this was even filmed.
The next logical step was to show AC’s deadliness on human beings themselves. Edison, realizing that he was losing the war, again used his influence on the government, this time to promote the use of AC for the execution of prisoners. Thus, in 1890, the first ‘electric chair’ was constructed in anticipation of an impending death sentence. Westinghouse countered by hiring the best lawyers of the day to defend the prisoner in question, as well as to prevent the system of execution. Although he failed in both respects, the results were unexpected. Despite a botched execution and the horror of the spectators, the electric chair would remain, but AC would not be stigmatized as the killer Edison’s had hoped.
Meanwhile, AC’s range and efficiency saw Westinghouse being given high prestige engineering projects, such as the Ames Hydro-electric Generating Plant (1891), and another one on Niagara Falls, culminating in the greatest public relations victory in 1893: the contract to illuminate the Columbian Exposition in Chicago. Here, Tesla and Westinghouse showed the wonders of AC power with various electrical exhibits, such as fluorescent lamps and Tesla’s AC motors, to an awestruck audience and widespread press attention. After that, the war was effectively won, and AC would take over almost completely.

Solution and Explanation
Questions 14-17:
Complete the table.
Choose NO MORE THAN TWO WORDS from the passage for each answer.

Advantages	Disadvantages
Supply can be supplemented with 14	Wire resistance lowers the 15
could power 16 motors (only sort available then)	Supply distance is limited.
gave Edison income	Wires used are thick and 17

Question 14:

Answer: storage batteries
Supporting Sentence: It can allow storage batteries to be directly connected to the electricity grid
Keywords: can allow storage batteries, directly connected
Keyword Location: Para 3, line 1
Explanation: in order to connect to electricity grid DC is able to connect to storage batteries which is one of the benefits of DC

Question 15:

Answer: (the) voltage significantly
Supporting Sentence: Due to low voltage, there is correspondingly higher current, meaning that the electrical resistance of the transmission wires significantly reduces the voltage as it travels further afield
Keywords: electrical resistance, wires significantly reduces the voltage
Keyword Location: Para 2, lines 5-6
Explanation: electrical resistance of the transmission wires significantly reduces because of the low voltage and high current that travels through the field

Question 16:

Answer: DC
Supporting Sentence: It can allow storage batteries to be directly connected to the electricity grid, giving extra power to meet sudden short-term peaks of demand, or backup during breakdown of supply.
Keywords: no practical AC motors, only DC ones
Keyword Location: Para 3, lines 3-4
Explanation: benefits of DC includes that by giving extra power short-term peaks of demand can be met or backup can be endured during the breakdown of electricity supply

Question 17:

Answer: expensive
Supporting Sentence: the best answer is to transform, or step-up, the voltage to very high levels for transmission, and then transform it down to safe levels for customer use
Keywords: allows thinner and less expensive wires
Keyword Location: Para 4, lines 4-5
Explanation: for effective customer use it is important to transform the voltage to high levels of transmission and then transform it to safe levels

Question 18-20:
Choose THREE answers from the list and write the correct letter, A-F, next to the questions.
Which THREE strategies, A-F, did Edison use to discredit AC current?

Hired lawyers
Pressured politicians
Invented many DC devices
Used movie cameras
Scared people
Invented the electric chair

Question 18:

Answers: B
Supporting Sentence: Westinghouse countered that such risks could be minimized and were considerably outweighed by the benefits.
Keywords: Edison’s, influence, American state governments
Keyword Location: Para 7, lines 3-4
Explanation: Edison further discredited the risks that could be minimized by AC which was countered by Westinghouse

Question 19:

Answers: D
Supporting Sentence: In the battle of public opinion, this was even filmed
Keywords: this was even filmed
Keyword Location: Para 7, last line
Explanation: the fact Edison was prepared to conduct electrocutions publicly of animals by AC on a rogue elephant which was not wanted by any circus, in public opinion was also filmed.

Question 20:

Answers: E
Supporting Sentence: Edison's first strike was to claim that high-voltage systems were too dangerous to use.
Keywords: Edison’s, claim, high-voltage systems, too dangerous to use
Keyword Location: Para 7, line 1
Explanation: the first counter made by Edison was that high-voltage systems were too dangerous to use

Questions 21-26:
Answer the questions.
Choose the correct letter, A, B, or C.

A	Edison and Tesla
B	Edison and Westinghouse
C	Tesla and Westinghouse

Who

favored AC?
started a company?
had a face-to-face fight?
invented many devices?
owned many patents?
was well educated?

Question 21:

Answers: C
Supporting Sentence: the voltage to very high levels for transmission, and then transform it down to safe levels for customer use; One of the converts to the cause was a university-trained electrical engineer named George Westinghouse, and he was willing to invest in the idea
Keywords: AC, Nikola Tesla, researched George Westinghouse, patents, AC-based, technology
Keyword Location: Para 4, lines 5-6; Para 6, lines 3-4
Explanation: Edison stated that high levels of transmission from voltage can be done through safe levels for better customer use while Tesla stated that Westinghouse was willing to invest in the idea hence, favoring the AC

Question 22:

Answers: B
Supporting Sentence: but Edison needed an efficient electricity distribution system to capitalise on this; One of the converts to the cause was a university-trained electrical engineer named George Westinghouse, and he was willing to invest in the idea
Keywords: he founded the Edison Illuminating Company; Westinghouse, formed a company
Keyword Location: Para 2, lines 2-3; Para 6, lines 3-4
Explanation: Edison needed an efficient system of distribution of electricity while Westinghouse was willing to invest in the idea that developed Tesla

Question 23:

Answers: A
Supporting Sentence: was able to understand AC's potential, even inventing an AC polyphase electric induction motor
Keywords: direct confrontation
Keyword Location: Para 5, line 6
Explanation: Edison and Tesla were able to understand the the potential of AC by inventing an AC polyphase electric induction motor

Question 24:

Answers: A
Supporting Sentence: Most of the load consisted of incandescent light bulbs which ran well on DC
Keywords: Edison had, patents, many, DC devices, he, invented
Keyword Location: Para 3, lines 5-6
Explanation: Edison and Tesla supported the statement of incandescent light bulbs which they favored ran well on the DC

Question 25:

Answers: B
Supporting Sentence: Most of the load consisted of incandescent light bulbs which ran well on DC; One of the converts to the cause was a university-trained electrical engineer named George Westinghouse, and he was willing to invest in the idea
Keywords: Edison had, patents, many, DC devices, he, invented; George Westinghouse, purchased, patents
Keyword Location: Para 3, lines 5-6; Para 6, lines 3-4
Explanation: Edison and Westinghouse favored the idea of incandescent light bulb that favored DC and Westinghouse supported the investment idea for AC

Question 26:

Answers: C
Supporting Sentence: He had actually proposed the AC system to Edison, but Edison, an empirical experimenter with little formal education, dismissed it as impractical
Keywords: Tesla, mathematical training, formal theoretical knowledge
Keyword Location: Para 5, lines 3-4
Explanation: Tesla and Westinghouse were the most educated thereby proposed the AC system thereby dismissed it as impractical

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