2025 · Paper 1

Complete GATE ES 2025 Paper 1 overview, original pages and practice · Timed previous-paper practice

Questions 61–63 of 65. Imported answers require review unless explicitly marked reviewed.

Question 61

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An incandescent light bulb operated for two hours per day uses 12.2 kWh of energy per month. Burning of one kg of coal generates 2 kWh of electrical energy and releases 7 g of PM₁₀. The reduction in PM₁₀ emitted per month, if this incandescent bulb is replaced with a light emitting diode (LED) bulb that uses 1/6ᵗʰ of energy, is _____ g. (rounded off to one decimal place)

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Question 62

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A street sweeping machine starts from point P and ends at S, as shown in the network of streets below. It sweeps all the streets at least once.



Length of the streets, in km, are shown on the network. The minimum distance travelled by the sweeping machine for completing the job of sweeping all the streets is ______ km. (round off to nearest integer)

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Question 63

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ESNAT2 marksNeeds review

A solid waste of composition C



H



O



N



is to be composted aerobically in a closed vessel mechanical composting facility. Given: all ammonia generated escapes the facility; air contains 23% of Oxygen by weight; 100% excess air requirement for the closed vessel composting facility. The atomic weights: C – 12, H – 1, O – 16, N – 14. The actual air required for composting is ______ kg per kg waste. (rounded off to one decimal place)

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