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13 lessons,
1h 53m
Questions (11-17)
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In this lesson, questions (11-17) have been discussed.

Harshit Aggarwal
Cleared UPSC ESE twice with Rank 63 and 90 in mechanical engg. Got 99 percentile in GATE. Cracked ONGC, BHEL,ISRO, SAIL, GAIL successfully

Unacademy user
thanks sir , kindly add numerical videos along the existing subjects
  1. COURSE: Question on I C Engine Lesson: Question (11-17)

  2. About me Graduated from NIT Nagpur in 2008 Cleared Engineering Services Examination (ESE-UPSC) Exam Got the offer letter from most of the Maharatna and Navratna Companies Cleared GATE Exam Rate, Review, Recommend, Share Follow me on Unacademy at: aggarwal

  3. Common Data for Question 11 and Question 12 In two air standard cycles one operating on the Otto and the other on the Brayton cycle-air is isentropic ally compressed from 300 to 450 K. Heat is added to raise the temperature to 600 K in the Otto cycle and to 550 K in the Brayton cycle. If 17, and are the efficiencies of the Otto and Brayton cycles, then (a) 0-025, ,-0.18 (b) nn 0.33 (c)7, 0.5, ,-0.45 (d) It is not possible to calculate the efficiencies unless the temperature after the expansion is given Q. 12 If Wo and WB are work outputs per unit mass, thein (a) Wo> WB (b) Wo<WB (c) Wo-WB (d) it is not possible to calculate the work outputs unless the temperature after expansion is Given.

  4. Solution 11 3(600K) 3(550K) 2 (450K 2 (450 OK 00K Otto cycle Brayton cycle T 0 0.33 2 450 T. Ans b 0.33 450

  5. Solution 12 450 300 T. = 600 T. 900 K T, T T. T. 450 300 Brayton 1-2 | ' = 2-4 T, T 3 So Woto>WBrayton Ans a

  6. Question 13 A diesel engine is usually more efficient than a spark ignition engine because (a) diesel being a heavier hydrocarbon, releases more heat per kg than gasoline (b) The air standard efficiency of diesel cycle is higher than the Otto cycle, at a fixed compression ratio (c) The compression ratio of a diesel engine is higher than that of an SI engine (d) Self ignition temperature of diesel is higher than that of gasoline Ans: C

  7. Question 14 What does the reversed ideal Stirling cycle consist of? (a) Tow reversible isothermal processes and two reversible adiabatic processes (b) Two reversible isothermal processes and two reversible isochoric processes (c) Two reversible isobaric processes and two reversible adiabatic processes (d) Two reversible adiabatic processes and two reversible isochoric processes Ans b

  8. Question 15 Which cycle consists of two reversible isotherms and two reversible isobars? (a) Carnot cycle (c) Ericsson cycle (b) Stirling cycle (d) Brayton cycle Ans : C

  9. Question 16 Which one of the following p-T diagrams illustrates the Otto cycle of an ideal gas? Ans a

  10. Question 17 For maximum specific output of a constant volume cycle (Otto cycle) (a) The working fluid should be air (b) The speed should be high (c) Suction temperature should be high (d) Temperature of the working fluid at the end of compression and expansion should be equal Ans: d