mechanical engineering MCQs – Page 43

A. fixed carbon, ash, volatile matter, moisture

B. best analysis

C. higher calorific value

D. lower calorific value

A. unpredictable

B. same

C. less

D. less or more depending on size of boiler

A. high calorific value coal being burnt

B. raising of steam temperature

D. leakage of air

E. higher effectiveness of boiler

B. limitation of construction facilities

C. the draft to be created

D. all of the above

E. quantity of flue gases to be handled

A. chimney

B. induced draft fan

C. smoke meter

E. pulveriser

A. mix fuel with air and ignite

B. to provide proper conditions for con-tinuous complete combustion

C. to minimise radiation losses

E. maintain heat supply to prepare and ignite the incoming fuel

A. chimney

B. induced draft fan

C. both combined A. and B.

E. none of the above

A. pressure of steam in kg/cm2

C. temperature of steam in C

D. tonnes/hr. of steam

E. none of the above

A. it helps in electrostatic precipitation of ash in flue-gases

B. none of the above

C. it has heating value

E. it leads to corrosion of air heaters, ducting, etc. if flue gas exit temperature is low

B. heat release can be easily controlled

C. separate mills are required to powder the coal

D. fuel burns economically

E. high burning rate is possible

A. 200-400 kcal/kg

C. 5000-8000 kcal/kg

D. 8000-10,000 kcal/kg

E. 800-1200 kcal/kg

A. none of the above

B. regulate flow of boiler water

C. recirculate unwanted feed water

D. check level of water in boiler drum

A. Proof stress

B. Yield point stress

D. Fracture stress

A. 6 to 20

B. 220 to 345

C. 15 to 120

A. below dew-point temperature of flue gases

C. less than wet bulb temperature of flue gases

D. 100C

E. above wet bulb temperature of flue gases

B. saturated

C. supersaturated

D. superheated

E. dry

A. some moisture in coal helps in better burning which is not possible with completely dry coal

B. in some coals moisture may be present upto 40%

C. moisture in coal is removed before firing by heating it with hot air

D. inherent moisture and surface moisture are different things

A. Constant Volume cycle

B. All of above

C. Constant temperature cycle

A. various chemical constituents, carbon, hydrogen, oxygen, etc, plus ash as per-cents by weight

B. various chemical constituents, carbon, hydrogen, oxygen etc, plus ash as per-cents by volume

D. fuel constituents as percents by volume of moisture, volatile, fixed carbon and ash

E. moisture and ash free heating value

A. drooping characteristic

B. linear characterisstic

C. none of the above

D. flat characteristic

A. heating surface depends on other parameters

B. equal heating surface

C. less heating surface

E. none of the above

A. handling and maintenance should be easier

C. approach temperature should be as low as possible

D. none of the above

E. heat transfer area should be optimum

A. avoid explosion in furnace

B. support furnace freely from top

C. prevent atmospheric air leaking into furnace

D. prevent leakage of hot flue gases

B. embrittlement

C. carryover

D. scale

E. corrosion

B. unpredictable

C. remain unaffected

D. improve C. worsen

A. increase *heat transfer rate

B. increase steam parameters

C. all of the above

D. increase efficiency-of thermal power plant

E. reduce hardness and for removal of solids

B. 1.013 bar

C. 101.3KN/m2

D. 760mm of Hg

A. inductance

C. None of these

D. voltage

A. lower value

B. lower/higher depending on steam flow

C. unpredicatble

D. same value

A. increases

B. remains unchanged

D. unpredictable

E. increases/decreases depending on steam temperature requirements

A. Peat

B. Wood

D. Bituminous coal

A. produce minimum smoke and gases

B. ease in storing

C. ecomomical

E. high calorific value

A. None of these

B. Peat

D. Coal

A. Brown coal

B. Anthracite coal

C. Woodchar coal

B. 65.78lbf

C. 3.00989 lbf

D. 90lbf

A. Gasoline

B. Patrol

D. Paraffin

A. None of these

B. Equal

C. Higher

D. Lower

B. adiabatic compression

C. isentropic compression

D. botii isothermal and adiabatic compression

E. ideal compression

B. relief valve

C. start-stop motor

D. variable speed

E. none of the above

A. from any one of the above locations

B. from coal yard side

C. from outside atmosphere at 1C

D. from an air conditioned room maintained at 20C

A. may increase/decrease depending on clearance volume

B. increase

C. remain same

E. none of the above

A. to attain high volumetric efficiency

C. to avoid mechanical bang of piston with cylinder head

D. to provide cushioning effect

E. to accommedate Valves in the cylinder head

A. remain same

B. decrease

C. unpredictable

D. none of the above

A. air stream blocking the passage

C. air stream not able to follow the blade contour

D. production of no air pressure

E. motion of air at sonic velocity

A. may be less or more depening upon speed

C. same

D. none of the above

E. more

A. high friction losses

C. high pressure ratio

D. high specific volume

E. increasing gas temperature

A. minimum cycle temperature

B. maximum cycle temperature

C. none of the above

D. all of the above

A. resultant component

B. tangential component

D. radial component

A. none of the above

C. centrifugal pump

D. reciprocating pump

E. sliding vane compressor

A. passing steam over incandescent coke

B. passing air and a large amount of steam over waste coal at about 65C

C. carbonisation of coal

D. same way as the natural gas