Who studied Newcomen’s steam engine?
A.John Kay
B.Faraday
C.James Watt
D.George Stephenson

Hint:He was a famous Scottish inventor. He is the person who developed the concept of horsepower. He was the person who was interested in the technology of the steam engine. The SI unit of power is related to his name. He was fundamental to the changes brought by the Industrial revolution in the world.

Complete answer:
Thomas Newcomen is a British engineer who invented the atmospheric steam engine. This steam engine is a precursor of James Watt’s engine. Newcomen’s engine was studied by James Watt. Newcomen’s engine was the first practical fuel- burning engine invented in 1712. A steam engine was operated by transferring steam into the cylinder, by creating a vacuum which allowed the atmospheric pressure to push the piston into the cylinder. Newcomen’s engine was the first practical device to make use of steam to produce mechanical work. Many constructed this model in the eighteenth century.

James Watt was a famous Scottish inventor and mechanical engineer. Watt improved Newcomen's with his Watt steam engine in1776. James Watt had studied this engine and made an improved version of Newcomen’s engine that doubled the fuel efficiency. Many atmospheric engines were converted to Watt’s model of engines. Watt is today more famous than Newcomen concerning the origin of the steam engine. The main problem with Newcomen’s engine design was that it uses energy inefficiently, and it was very expensive to operate. James Watt improved Newcomen's engine in 1769to avoid this problem. But the Newcomen’s engine was not eliminated immediately, it was cancelled when Newcomen’s patents expired. Watt’s steam engine included better engineering techniques than Wilkinson's boring machine, which was more fuel-efficient. James Watt had brought many improvements and changes in the Newcomen’s engine. But at the same time, Newcomen’s engine was newly made as it is cheaper and less complicated than Watt’s engine. An element of Watt's design was a Separate Condenser, which was incorporated in many "pirate" engines.

Hence, the correct answer is option (C).

Note:Newcomen specialized in designing, manufacturing tools for industries. Newcomen engines were used throughout Britain and Europe to pump water out of mines. By 1800 hundreds of non-Watt engines had been built, where irregular motion was not a problem. Almost 2200 Newcomen’s engines were built in the eighteenth century, only about 450 Watt engines were built that time.