91. Who discovered the principles of the steam engine?
a) James Watt
b) Thomas Savery
c) Thomas Newcomen
d) George Stephenson
Answer: a) James Watt
92. Who invented the first practical refrigerator?
a) William Cullen
b) Carl von Linde
c) Jacob Perkins
d) John Gorrie
Answer: b) Carl von Linde
93. Who discovered the law of conservation of energy?
a) James Prescott Joule
b) Michael Faraday
c) Georg Simon Ohm
d) Lord Kelvin
Answer: a) James Prescott Joule
94. Who invented the first successful electric light bulb?
a) Thomas Edison
b) Joseph Swan
c) Nikola Tesla
d) George Westinghouse
Answer: a) Thomas Edison
95. Who discovered the principle of the steam turbine?
a) Charles Parsons
b) Robert Stirling
c) James Watt
d) George Stephenson
Answer: a) Charles Parsons