Free Technology and Energy MCQs with Answers

51. Atomic power plant works on the principle of?

• A. fission
• B. fusion
• C. thermal combustion
• D. combined effect of all the above three

Explanation: An atomic power plant splits heavy atomic nuclei, commonly uranium-235, in a controlled chain reaction. The released nuclear energy heats water to produce steam and electricity, so the basic principle is fission.

52. Which of the following circuit elements is used to 'block' DC in an electronic circuit ?

• A. Resistances
• B. Capacitance
• C. Inductance
• D. Diode

Explanation: A capacitor charges briefly and then blocks steady direct current, while allowing alternating current to pass depending on frequency. A resistor limits current and an inductor tends to oppose changes in current rather than simply block DC.

53. In a photocell light energy is converted into?

• A. potential energy
• B. chemical energy
• C. heat energy
• D. electrical energy

Explanation: A photocell uses the photoelectric effect to convert incident light into an electrical signal or current. It does not primarily convert light into heat, chemical energy or stored potential energy.

54. Which gas does a Photocopier machine produce?

• A. Ozone
• B. carbon dioxide
• C. Sulfur dioxide
• D. None of these

Explanation: Photocopiers can produce ozone when high-voltage corona wires ionise oxygen during the electrostatic copying process. Modern machines reduce this by using alternative charging systems and ozone filters.

55. A summary value calculated from population is called?

• A. Parameter
• B. Sample
• C. Statistic
• D. Population

Explanation: A numerical summary calculated from an entire population is called a parameter. The corresponding value calculated from a sample is called a statistic.

56. Lignite, bituminous & anthracite are different rank of _________ ?

• A. Iron
• B. Coal
• C. Wood
• D. None of these

Explanation: Lignite, bituminous coal and anthracite represent increasing ranks of coal, mainly reflecting increasing carbon content and degree of coalification. Anthracite is the hardest and most carbon-rich of these three.

57. Which of these is NOT a form of energy?

• A. Heat
• B. Light
• C. Temperature
• D. Electricity

Explanation: Temperature measures how hot or cold something is, whereas heat, light and electricity are forms of energy or energy transfer. Temperature and heat are related but are not the same physical quantity.

58. Which of these is NOT an example of a renewable energy source?

• A. Wind energy
• B. solar
• C. Coal
• D. Hydroelectric power

Explanation: Coal is a fossil fuel formed over millions of years, so its supply is finite and non-renewable. Wind, sunlight and flowing water are naturally replenished.

59. For the generation of biogas, the materials commonly used are__________?

• A. Animal wastes
• B. Forest residues
• C. Aquatic plants
• D. None of these

Explanation: Animal waste is commonly fed into an oxygen-free digester, where microorganisms break it down to produce methane-rich biogas. Other organic residues can also be used, but animal waste is the standard answer here.

60. An ordinary mobile phone communicate by using___________?

• A. Sound waves
• B. Infrared waves
• C. UV waves
• D. Radio waves

Explanation: Mobile phones communicate with cellular networks using radio-frequency electromagnetic waves. Sound is converted into electrical signals, whereas infrared and ultraviolet waves are not used for ordinary cellular communication.