Unit 1: Introduction to farm power and mechanization - Practice Quiz

1 What is meant by farm power?

2 Which of the following is a traditional source of farm power?

3 Which source of power is commonly used in modern tractors?

4 Which of the following is a renewable source of farm power?

5 What is the main objective of farm mechanization?

6 Which is a major benefit of farm mechanization?

7 Farm mechanization can help reduce:

8 Which factor can limit the use of farm machinery by small farmers?

9 The scope of farm mechanization includes operations such as:

10 What does I.C. engine stand for?

11 The upper limit of piston movement in a cylinder is called:

12 The lower limit of piston movement is called:

13 The distance travelled by a piston between TDC and BDC is called:

14 The inside diameter of an engine cylinder is called the:

15 In an I.C. engine, combustion takes place:

16 What is the main function of the piston in an I.C. engine?

17 Which component converts reciprocating motion into rotary motion?

18 A two-stroke engine completes one working cycle in:

19 In a typical two-stroke engine, gas exchange is controlled mainly by:

20 A four-stroke engine completes one working cycle in:

21 A farmer needs to operate an irrigation pump regularly in an area with reliable electricity but expensive diesel. Which power source is generally the most economical for this stationary operation?

22 A solar-powered pump must supply water even during cloudy periods. Which addition would most directly improve the reliability of the system?

23 Which farm power source is most suitable for precision field operations requiring high mobility and controlled forward speed?

24 A farmer replaces manual harvesting with a combine mainly because an approaching storm may damage the mature crop. Which objective of mechanization is most relevant?

25 In a region dominated by small and fragmented farms, which approach best addresses the high ownership cost of machinery?

26 A mechanical rice transplanter reduces the number of workers needed and maintains nearly uniform plant spacing. Which pair of benefits is demonstrated?

27 Which situation is most likely to limit the effective use of a large four-wheel tractor?

28 A single-cylinder engine has a bore of and a stroke of . What is its approximate swept volume?

29 An engine has a swept volume of and a clearance volume of . What is its compression ratio?

30 An engine develops an indicated power of and a brake power of . What is its mechanical efficiency?

31 An engine with a stroke length of operates at . What is its mean piston speed?

32 Why does a compression-ignition engine normally use a higher compression ratio than a spark-ignition engine?

33 In a conventional spark-ignition engine, what is compressed in the cylinder before ignition?

34 The flywheel of a single-cylinder I.C. engine stores energy during the power stroke. What is the main purpose of releasing this energy during the remaining strokes?

35 A single-cylinder four-stroke engine runs at . How many power strokes occur per minute?

36 During the compression stroke of a four-stroke diesel engine, which condition is correct?

37 If the inlet valve of a four-stroke engine fails to open during the suction stroke, what is the most direct result?

38 A single-cylinder two-stroke engine operates at . How many power strokes ideally occur per minute?

39 In a two-stroke engine, fresh charge entering the cylinder helps push out the remaining exhaust gases. What is this process called?

40 Compared with a four-stroke engine of similar size and speed, why can a two-stroke engine produce greater power per unit displacement?

41 A farm requires 120 kWh of useful mechanical energy during a critical 10-hour period. An electric motor is available for only 6 hours and delivers 12 kW at 90% efficiency. A diesel engine-generator delivers mechanical power at 30% overall efficiency. If electricity is used whenever available, how much fuel energy must the diesel system supply?

42 A region reports rising tractor power per hectare but unchanged timeliness of sowing. Which additional observation most strongly explains this apparent contradiction?

43 A 10 ha field is tilled using a 2.4 m implement at 6 km/h. Field efficiency is 75%. Ignoring downtime outside the field, approximately how long is required?

44 A small farm can mechanize only one operation. Yield losses are 3% from delayed land preparation, 12% from delayed sowing, 4% from nonuniform weeding, and 8% from delayed harvesting. Assuming similar annual ownership cost for each machine, which choice best meets the objective of selective mechanization?

45 Which situation most directly converts fragmented landholding from a mechanization limitation into a manageable constraint?

46 A combine reduces harvesting cost by per hectare and prevents crop loss worth per hectare. Its annual fixed cost is , and variable machine cost is already included in the stated cost reduction. What minimum annual area makes the investment break even?

47 A four-cylinder engine has a bore of 100 mm and a stroke of 120 mm. What is its total swept volume?

48 The swept volume of one cylinder is 540 cm. If the compression ratio is 10:1, what is the clearance volume?

49 An engine develops 40 kW indicated power and 32 kW brake power. Which pair correctly gives friction power and mechanical efficiency?

50 An engine with a stroke of 110 mm runs at 2400 rpm. What is its mean piston speed?

51 A tractor engine delivers 18 kW brake power at 1500 rpm. Approximately what crankshaft torque does it produce?

52 In an ideal air-standard Otto cycle, increasing the compression ratio while keeping the heat supplied and specific-heat ratio constant primarily causes which result?

53 A compression-ignition engine receives fuel with an excessively long ignition delay. Which outcome is most likely when combustion finally begins?

54 During a motoring test, an engine is driven at its normal speed without combustion. The measured driving power is commonly used to estimate which quantity?

55 In a crankcase-scavenged two-stroke spark-ignition engine, a leaking crankshaft seal most directly causes which coupled effect?

56 A single-cylinder two-stroke engine and a single-cylinder four-stroke engine both run at 3000 rpm. Assuming every cycle fires, how many power strokes per minute do they produce, respectively?

57 If the transfer port of a piston-ported two-stroke engine opens substantially earlier while exhaust-port timing is unchanged, what is the most likely penalty?

58 Why is the inlet valve commonly closed after bottom dead center in a high-speed four-stroke engine?

59 Increasing valve overlap in a four-stroke engine can improve high-speed breathing but reduce low-speed stability. Which mechanism best explains both effects?

60 A four-stroke engine has a total swept volume of 2.0 L and runs at 2400 rpm. At standard intake conditions it draws 2.16 m/min of air. What is its volumetric efficiency based on swept volume?