Q50. Which waste is commonly used in a household biogas digester?
[MP Forest Guard, 12 June 2023]
(A) Plastic bottles
(B) Broken glass
(C) Cattle dung
(D) Metal filings
Answer: C. Cattle dung
Explanation: Cattle dung contains biodegradable matter and microorganisms suitable for anaerobic digestion. In a sealed digester it produces methane-rich gas for cooking or heating. The digested slurry can return nutrients to agricultural fields.
Q49. What is the chief combustible gas in biogas?
[UPSC CAPF, 2023]
(A) Methane
(B) Carbon dioxide
(C) Nitrogen
(D) Oxygen
Answer: A. Methane
Explanation: Anaerobic digestion produces a methane-rich gaseous fuel from wet organic residues. Methane burns to release energy, whereas carbon dioxide contributes little heating value. Biogas offers a practical link between rural waste management and renewable fuels.
Q48. Which turbine feature strongly influences the energy captured by a wind turbine?
[NHPC/THDC Junior Engineer, 23 July 2023]
(A) Colour of the tower
(B) Blade length or swept area
(C) Paint thickness
(D) Nameplate lettering
Answer: B. Blade length or swept area
Explanation: Longer blades generally sweep a larger area, allowing a turbine to intercept more moving air. Actual output also depends on wind speed, machine design and operating limits. Wind-power potential is therefore highly site-dependent.
Q47. What was Madhya Pradesh’s rank in gross coal production in the data referred to by this exam?
[MPPSC State Services (2022 cycle), 21 May 2023]
(A) Second
(B) Third
(C) Fourth
(D) Fifth
Answer: C. Fourth
Explanation: The paper used a particular reporting period in which Madhya Pradesh was fourth by gross coal output. Such rankings change over time. The state has significant coalfields around Singrauli, Sohagpur and Satpura-basin districts.
Q46. In which year was Bihar State Hydroelectric Power Corporation established?
[Bihar STET, 18 September 2023]
(A) 1975
(B) 1979
(C) 1982
(D) 1995
Answer: C. 1982
Explanation: Bihar State Hydroelectric Power Corporation was established in 1982 to develop hydroelectric resources and associated infrastructure. Small and medium hydel projects can supplement other electricity sources, depending on river flow and feasible head.
Q45. Which conventional fuel has long provided the largest part of India’s power supply?
[SSC CHSL, 14 August 2023]
(A) Petroleum
(B) Natural gas
(C) Coal
(D) Firewood
Answer: C. Coal
Explanation: Coal has historically supplied most of India’s grid electricity generation. Large coal-fired stations operate near mining regions and demand centres. The installed mix is changing with solar and wind growth, but coal remained predominant in the examined period.
Q44. Which state has the notable Neyveli lignite deposits?
[SSC CHSL, 7 August 2023]
(A) Gujarat
(B) Rajasthan
(C) Tamil Nadu
(D) Odisha
Answer: C. Tamil Nadu
Explanation: Neyveli in Tamil Nadu is a major lignite-mining and lignite-fired generation centre. Brown coal contains relatively high moisture and lower carbon concentration. Its local use in nearby stations limits the cost of carrying low-grade fuel long distances.
Q43. The Neyveli coalfield is especially associated with which mineral fuel?
[SSC CGL, 21 July 2023]
(A) Anthracite
(B) Coking bituminous coal
(C) Petroleum
(D) Lignite
Answer: D. Lignite
Explanation: Neyveli is one of India’s best-known lignite resources. Lignite is also called brown coal and lies below bituminous coal in rank. Mining supports thermal electricity and industrial fuel uses in the Tamil Nadu region.
Q42. The floating solar-power plant at Ramagundam is located in which state?
[SSC MTS, 6 September 2023]
(A) Odisha
(B) Andhra Pradesh
(C) Telangana
(D) Karnataka
Answer: C. Telangana
Explanation: NTPC’s Ramagundam floating solar installation occupies a reservoir surface in Telangana. Floating photovoltaic arrays can generate power without acquiring equivalent dry land. Their design must accommodate water movement and local environmental conditions.
Q41. Kapurdi lignite mines are situated in which Rajasthan district?
[Rajasthan CET, 5 February 2023]
(A) Bikaner
(B) Barmer
(C) Jaisalmer
(D) Nagaur
Answer: B. Barmer
Explanation: Kapurdi is associated with Barmer’s lignite-bearing deposits and power development in western Rajasthan. Lignite is a comparatively young, moisture-rich coal. Local mining and generation can support electricity supply without shipping fuel from distant coalfields.
