Free Technology and Energy MCQs with Answers

101. On passing through food stuff, X-ray can kill the___________?

• A. Fungus
• B. Virus
• C. Bacteria
• D. insects

Explanation: Food irradiation with X-rays is used mainly to destroy bacteria and other microorganisms, helping extend shelf life and improve safety. The standard answer for this general food-preservation question is bacteria.

102. What is/are the basic purpose(s) of dams?

• A. Storage of water in a large reservoir
• B. Generation of electricity
• C. Control of floods
• D. All of the above

Explanation: Dams can store water, generate hydroelectric power and regulate floods, although their actual functions depend on their design. Therefore all three listed purposes are valid.

103. What is the element required for solar energy conversion ______?

• A. Ultra pure carbon
• B. Silicon
• C. Beryllium
• D. Tantalum

Explanation: Silicon is a semiconductor whose electrical properties allow solar cells to convert light energy into electrical energy. Ultra-pure silicon is commonly used because impurities strongly affect its conductivity.

104. The oldest barrage on the river Indus at Sukkur was built in_____?

• A. 1932
• B. 1940
• C. 1930
• D. 1928

Explanation: The Sukkur Barrage on the Indus was completed in 1932 and began regulating irrigation water from the river. It is also known as Lloyd Barrage.

105. The common refrigerant used in domestic Refrigerator is_____________?

• A. Neon
• B. Spirit
• C. Freon/Ammonia
• D. Methane

Explanation: Domestic refrigerators traditionally used Freon-type refrigerants, although many modern models use newer, less ozone-damaging alternatives. Ammonia is mainly associated with industrial refrigeration, so the combined option is an outdated but intended choice.

106. Who invented the safety pin?

• A. Charles Goodbye
• B. steward Harshone
• C. Walter Hunt
• D. A.Rose

Explanation: Walter Hunt patented the modern safety pin in 1849, designing it with a clasp that protects the sharp point. The other names are not associated with this invention.

107. Who developed the telegraph code?

• A. Andre Ampere
• B. Samuel Morse
• C. Joseph Henry
• D. Jean Fourier

Explanation: Samuel Morse developed the code used with the telegraph, now called Morse code. It represents letters and numbers through combinations of dots and dashes.

108. Diesel engine was discovered by___________?

• A. Paul Muller
• B. Faraday
• C. Waldeyer
• D. Rudolf Diesel

Explanation: Rudolf Diesel developed the compression-ignition engine, which is therefore called the diesel engine. It ignites fuel using the heat produced by compressing air rather than a spark plug.