agriculture engg. and science

8/10/2019 agriculture engg. and science

1/90

Trial Examinationfor

GATE 2006

Department of Agricultural Process

Engineering


2/90

Group I

Question No. 1 to 20 will carry one mark each

Time for Each Question = 25 Seconds


3/90

Q 1. : The Tylers standard screen scale is based on

standard opening of ----------

a. 28 mesh b. 48 mesh

c. 100 mesh d. 200 mesh


4/90

Q.2.: The paddy dehusking machine has two rubber

rolls that rotate with -------.

a. identical speed in same direction

b. identical speed in opposite direction

c. differential speed in same direction

d. differential speed in opposite direction


5/90

Q.3 : Oil content (whole mass basis) in rice bran

ranges between -------.

a. 8 to 10 %

b. 11 to 16 %

c. 17 to 22 %

d. 23 to 35 %


6/90

Q.4.: Energy requirement to grind a material is

expressed by --------

a. Ficks law

b. Newtons law

c. Kicks law

d. Stokes law


7/90

Q.5: Soybean is mostly used in India for production of

-----------.

a. edible oil

b. pulses

c. milk substitutes

d. processed food


8/90

Q.6. : If the atmospheric air is heated -------------.

a. its RH will increaseb. its RH will decrease

c. its AH will increase

d. its AH will decrease.


9/90

Q.7 : Milling of paddy is done in the moisture (w.b.)

range of -----------.

a. 8 - 10 % b. 10 - 12 %

c. 12 - 14 % d. 14 - 16 %


10/90

Q.8 : Compared to raw rice, milled rice obtained from

parboiled paddy -----------------.

a. is whiter and contains more vitamin B1

b. requires less cooking time and contains more vitamin B1

c. gives higher head yield and contains more vitamin B1

d. has more oil in bran and contains less vitamin B1


11/90

Q.9.: In drying, FMC of grain is defined as the

difference between ------

a. IMC & FMC b. IMC & EMC

c. IMC & CMC d. CMC & EMC


12/90

Q.10 : Machine used for dehusking of pulse is ---------

--------

a. rubber roll dehusker

b. emery roll dehusker

c. centrifugal dehusker

d. under runner disc sheller


13/90

Q.11: Pressure drop in fluid flow through granular

material is the best estimated by --------.

a. Black-Kozney equation

b. Burky-Plummer equation

c. Ergun equation

d. Fourier equation


14/90

Q.12 : In multiple effect evaporator concentration ofliquid food is difficult in last effect because ------.

a. the vacuum level is low

b. the temperature is low

c. flow rate is reduced

d. viscosity of liquid is large


15/90

Q. 13 : In transient heat transfer problems, the

dimensionless number used is -------------

a. Nusselt number b. Prandit number

c. Biot number d. Schmidt number.


16/90

Q.14 : ____________ indicates the relative

proportions of the coarse, medium and fine particles.

a) Fineness modulus

b) Uniformity index

c) Average particle size

d) Effectiveness


17/90

Q.15: If D is the cone diameter in mm then number

of brakes on a cone polisher is given by -------------.

a. (100/D)- 2 b. (D/ 100)- 2

c. 2+ (D/ 100) d. (100/ D)+ 2


18/90

Q. 16 : The EMC at 100% RH is known as ----------.

a. bound water b. unbound water

c. free water d. saturation water


19/90

Q.17 : Long term frozen storage of perishable must be

carried but below ----------------------.

a. 0oC b.10oC

c.18oC d.25 oC


20/90

Q.18 : Pasteurization of milk is necessary for ___.

a. long shelf life at room temperatureb. destruction of all microorganisms

c. destruction of only pathogenic microorganisms

d. long shelf life under refrigeration


21/90

Q. 19 : The major protein in wheat flour is

a. zein b. gluten

c. orygenin d. hordonin


22/90

Q. 20 : Jenssens equation is related to _____.

a. storage silo designb. size reduction of particles

c. grain transportation system

d. size separation of grains


23/90

Group IIQuestion No. 21 to 75 will carry two marks each


24/90

Q. 21. Total solids (TS) in fruit juice is to be

increased from 15 % to 50 % in an evaporator. The

% of initial water to be removed is about ------------.

a. 68 b. 72

c. 78 d. 82


25/90

Q. 22: Thermal resistance of 1 mm thick stainless

steel sheet of 1 m2area with thermal conductivity

of 15 W/ m0K is ------------ 0K/ W

a. 6.67 X10-5 b. 9.1 X 10-2

c. 15 d. 15000


26/90

Q.23: Three consecutive sieve and pan retain 20%,

50%, 20% &10 % of ground material respectively.

The fineness modulus of the ground material is------

---------.

a. 1.2 b. 1.8

c. 2.4 d. 3.5


27/90

Q.24: A herd of 100 dairy cows are fed 1300 kg of

silage daily. The thickness of silage fed each day is

100 mm. If one m3of silage weighs 650 kg, the

diameter of pit silo will be --------------.

a. 4.54 m b. 5.04 m

c. 5.64 m d. 6.04 m


28/90

Q. 25 Osmotic pressure of salt solution made up of

one litre and 10 gm sodium chloride at 30 oC is -----

------.

a. 4.31 bar b. 202.65 kPa

c. 2 bar d. 15 mbar


29/90

Q.26 : If 5 HP are required to reduce a material

from 2 cm size to 0.5 cm size. How much energy

would require if the reduction were to be 0.4 cm.

Use only Kicks law.

a. 5.80 b. 6.66

c. 3.66 d. 3.33


30/90

Q. 27 : Find the equilibrium moisture content of

wheat at RH = 10 % and t= 60 oC. The value of C

and n are taken as 3.11 x 10-7and 2.31 respectively.

using Hendersons equation.

a. 10.04 b. 20.04

c. 30.04 d. 40.04


31/90

Q.28 : A screw conveyer is mounted on 4 cm diashaft. It has pitch and diameter both equal to 30

cm. If its operating speed is 150 rpm then its

theoretical capacity is ------m3/ min.

a. 10.4 b. 3.12

c. 2500 d. 3.978


32/90

Q.29: The amount of juice concentrated containing

65 % solids & single strength juice containing 15 %

solids that must be mixed to produce 100 kg of

concentrate containing 45 % solids is -----------kg.

a. 40 b. 50

c. 60 d. 100


33/90

Q. 30: A single effect evaporator is required to

concentrate a solution from 10 % solids at the rate

of 250 kg of feed per hour . The rate of production

of juice concentrating 30 % solids is ------------

kg/hr.

a. 225 b. 167

c. 58.33 d. 83


34/90

Q. 31: Potatoes are dried from 14 % total solids to

93 % total solids. The product yield from each 100

kg of raw potatoes assuming that 8 % by weight of

original potatoes are lost in peeling is -----------.

a. 92 % b. 86.1%

c. 13.9% d. 1.39%


35/90

Q.32 : A thermal process is accomplished by

instantaneous heating to 138 oC followed by a foursecond hold & instantaneous cooling. Estimate the

leathality (F- value) at 121 oC when thermal

varison () for m.o. is 8.5o

C.

a. 4 sec b. 40 sec

c. 400 sec d. 0.4sec


36/90

Q.33 A wet food product contains 70 % water.After drying it is found that 80 % of original water

has been removed. The water removed during

drying per kg of wet food is ------------ kg.

a. 0.7 kg b. 0.8 kg

c. 0.56 kg d. 0.14 kg.


37/90

Q.34 : Food is milled from 6 mm to 0.0008 mmusing a 15 hp motor. The motor required to reduce

the size of particles 0.0012 mm will be ----------------

hp. Assume only Rittingers law.

a. 5 b. 10

c. 12 d. 15


38/90

Q.35: The F value at 121.1 oC equivalent to 99.999

% in activation of a strain of C boiling is 1.2 min.

The Do value of this organism is ------

a. 6 min b. 0.24 min

c. 1.2 min d. 2.4 min


39/90

Q.36 A thin walled pipe of stainless steel with Ks =

19 W/ moK with 2 cm 1D and 4 cm 0D is

maintained at 120oC & outside insulation at 90 oC.

The heat loss per meter pipe length is --------------.

a. 10.80 w/m b. 20.80 w/m

c. 30.80 w/m d. 40.80 w/m


40/90

Q.37 :Cream of 40 % fat and milk of 3 % fat is fed to

homogenizer to make 100 Kg standard milk of 5 %

fat . The quantity of cream to be mixed to milk is -----

----------Kg.

A) 3.6 B) 5.4

C) 94.6 D) 96.4


41/90

Q.38 : The amount of ice at 0oc to be mixed

adiabatically with 1 kg of water at 50oc such that the

temperature of the resulting water becomes ooc is

______kg.

A) 2.09 B) 1 kg

C) 0.626 kg D) 0.374


42/90

Q.39 : A manometer is used to measure the

pressure difference between two points in a pipehaving water, the height of mercury column is 50

mm , other fluid used in manometer is water with

density of 1000 kg/m

3

and the density of Hg is 13.6X 103kg/m3. The value of pressure difference is

_________ N/m2

A) 61.803 B) 123.606

C) 61803 D) 123606


43/90

Q.40 : Velocity of 2 micron diameter fat globules

inside a centrifuge operating at 5000 rpm has beenestimated to be 0.2 mm/s . The velocity of 1 micron

diameter fat globules inside the same centrifuge

operated at 6000 rpm will be ----------

A) 0.02 mm/s B) 0.2 mm/s

C) 0.72 mm/s D) 0.072 mm/s


44/90

Q. 41: Water at 20oc is being pumped through a 50mm diameter pipe at the rate of 2.5 kg/s. The mean

velocity of water in the pipe will be ---------m/s

A) 1.276 B) 25.05

C) 12.76 D) 2.505

h l h d h f f


45/90

Q. 42 : Thermocouples attached at the two faces of

stainless steel plate of 2 cm thickness indicate the

temperature of 105

o

c and 85

o

c. assume no heattransfer from sides and steady state heat transfer

prevails. Thermal conductivity of stainless steel may

be taken as 18 w/m k. Therefore the rate of heat

transfer through the plate is ----------.

A) 18 w/m2 B) 180 w/m2

C) 1800 w/m2 D) 18000w/m2


46/90

Q. 43 : Overall heat transfer coefficient of a

continuous ice cream freezer is 600w/m2k. The

temperature difference between ice cream mix andevaporating refrigerant is 25 ok . speed of two scraper

blade s inside the freezer is 150 rpm . If density of ice

is 917 kg/m3and latent heat of crystallization is 339

KJ/Kg . The maximum thickness of ice layer will be --

--------

A) 10m B) 10 mm

C) 10 cm D) can not predict


47/90

Q.44: The amount of water to be evaporated from 1kg of 5 % sugar solution at 30 oc to concentrate it

upto a level of 50 % is ---------

A) 0.1 kg B) 0.4 kg

C) 0.5kg D) 0.09 kg


48/90

Q. 45 1000 kg milk at 80 oc having specific heat

3900 J/kg is required to be heated to 140 oc by

injecting saturated steam at 150 oc . If the latent

heat of steam at 150 oc is 2115 KJ/kg and specific

heat of liquid water to be 4184 J/kg the amount ofsteam required to be injected into the milk is ------.

A) 100 kg B) 108.5 kgC) 1000 kg D) 10849 kg


49/90

Q.46 : The air in the room is at 26.7o

c and apressure of 101.325 kPa and contains water vapour

with partial pressure of 2.76 kPa . The value of

saturation vapour pressure is 3.5 kPa. The %

relative humidity of the air will be ---------

A) 62.23 % B) 65.35 %

C) 78.86 % D) 84.79 %


50/90

Q. 47: Air at 50 oc and 15 % relative humidity at

atmospheric pressure. The saturation vapour

pressure of water at 50 oc is 12.35 kPa. The specific

volume and absolute humidity of the given air will

be--------- respectively.

A) 0.0116 m3/kg and 0.9419 kg/kg

B) 0.0116 kg/kg and 0.9419 m3/kg

C) 0.9419 m3

/kg and 0.0116 kg/kgD) 0.9419 kg/kg and 0.0116 m3/kg


51/90

Q. 48: A sample of rice was dried at 45o

c . Themoisture content at 2 and 5 hrs were 21 % and 16

% dry basis respectively. If the drying constant K

equals to 0.426 per hr. The value of EMC of rice

will be ---------%.

A) 14.14 B) 16.16

C) 21.21 D) 35.35


52/90

Q. 49 : Orange juice has 16 % total solids initially.If the concentration of the total solids of the juice is

to be increased to 40 %, the fraction of initial water

to be removed from the juice is ---------.

a. 0.42 b. 0.63

c. 0.71 d. 0.84


53/90

Q.50: Relative humidity of air at 100oC and one

atmospheric pressure is 10%. If the ratio of

molecular weights of water to air is 0.62, the

absolute humidity of the air will be..

a. 0.0345 kg water/ kg dry air

b. 0.0752 kg water/ kg dry air

c. 0.0689 kg water/ kg dry aird. 0.0445 kg water/ kg dry air


54/90

Q. 51: If 10 W/m2heat flux is conducted across a

wall of 2 cm thickness experiencing a temperature

gradient of 2oC, the thermal conductivity of the

wall will be ----W/ m0K.

a. 1 X10-3

b. 1 X 10-2

c. 1 X10-1

d. 1 X 100


55/90

Q. 52 A roller mill converts 100 kg h-1of wheat

grits into flour. If the Bonds energy constant for

wheat grit is 3.02 kw h tonne-1mm-1/2, the power

required to grind the grits from an average particle

diameter of 3 mm to 0.1 mm is ________

a) 0.92 kW

b) 0.78 kW

c) 0.30 kWd) 0.25 kW


56/90

Q. 53 Average particle size of wheat flour having3.53 fineness modulus is _______

a) 1 mm

b) 1.1 mm

c) 1.2 mm

d) 1.3 mm


57/90

Q.54 : At a certain stage of fluidization, the height

and porosity of a bed of granular material are 5 cm& 0.4 cm respectively. If the height is increased to 6

cm by increasing air velocity, The porosity of bed

will be _______

a) 0.30

b) 0.45

c) 0.50d) 0.60


58/90

Q. 55: If the capacity of bucket elevator is 80 kg /

sec. The spacing between the bucket is 500 mm.

The bulk weight of material is 600 kg / m3& the

speed of the belt is cm / Sec. The buckets are filled

3/4thof its capacity. The capacity of each bucket in

liter is ________

a) 17.7

b) 23.6c) 27.7

d) 13.6


59/90

Q. 56 : 40 kg syrup contains 20 wt % sucrose.

Citric acid is added into the syrup such that itsconcentration in the resultant syrup is 3 wt %. The

amount of citric acid added to the syrup is

__________

a) 0.96 kg

b) 1.20 kg

c) 1.24 kgd) 1.48 kg

Q. 57 A wet material is dried inside a tray using air at


60/90

Q. 57 A wet material is dried inside a tray using air at

650C(db) and 500C(wb). If the heat transfer coefficient

on the surface of material is 10 W/m2Kand latent heat

of vaporization of water at 650C(db) and 500C(wb) are

2346 and 2406 kJ/kg respectively. The rate of drying

in kg water removed per square meter of exposed

surface per hour is ___

a) 2.302 kg of water /hr

b) 0.2302 kg of water /hrc) 2.245 kg of water /hr

d) 0.2245 kg of water /hr


61/90

Q. 58 In a sieve analysis, it is found that allmaterial retained a 48-mesh sieve. The average

diameter of particle is _________

a) 0.164 mm

b) 0.233 mm

c) 0.355 mm

d) 0.416 mm


62/90

Q.59 : Determine the diameter of pit silo having

depth 3 m and used to feed 100 cows for 15 days

each consuming 15 kg silage per day having density

650 kg / m3.

a) 3.28 m

b) 3.83 m

c) 2.08 md) 5.48 m


63/90

Q. 60 In sieve analysis 40 % material retained on28 mesh & remaining on 100 mesh. The fineness

modulus for above sieve analysis is ________

a) 0.8

b) 1.0

c) 1.2

d) 1.8


64/90

Q. 61 : A solution of common salt in water isprepared by adding 20 kg of salt to 100 kg of water

what is the concentration of weight faction.

a) 20 %

b) 11.7 %

c) 16.7 %

d) 15.8 %


65/90

Q. 62 : Calculated the radius of neutral zone so that

the feed inlet can be designed. If cream separator

has discharge radial of 4 cm and 8 cm & density of

skim milk is 1032 kg /m3and cream is 865 kg /m3

a) 0.012 m

b) 0.018 m

c) 0.12 md) 0.18 m

Q 63 C t d bl h d i f lifl


66/90

Q.63 Cut and blanched pieces of cauliflower are

dehydrated in a cabinet dryer. The initial moisture

content was 80 % (wb) it is to be dried to 4 % (wb)moisture content. The critical moisture content is

25 % (wb) constant rate drying continues for 6

minutes, estimate the total drying time for the

product.

a) 7.133 minutes

b) 8.313 minutesc) 6.454 minutes

d) 5.118 minutes


67/90

Q. 64: A processing plant is producing minced

meat, which must contain 18 % of fat. If this is tobe made up from boneless cow beef with 24 % of

fat and from boneless bull beef with 8 % fat what

are the proportions in which these should be mixed.

a) 55.6, 44.4

b) 62.5, 37.5

c) 64.0, 36.0d) 45.5, 54.5


68/90

Q. 65 Calculate the head of water equivalent to

standard atmospheric pressure of 1 atmosphere.

a) 1 mb) 10 m

c) 10.33 m

d) 9.6 m


69/90

Q. 66 Air contains 79 parts of nitrogen to 21 parts

of oxygen, what is the mole fraction of oxygen.

a) 0.79b) 0.21

c) 0.77

d) 0.23

67 M t h th i


70/90

67 Match the pairs

Group A Group B

P Particle size distribution in a

mixture of comminuted solid.

1. Fickslaw

Q Molecular diffusion in solid 2. Hagen-poiseulli equation

R Thermal sterilization of food 3. Q 10

S Moisture sorption isotherm 4. Fineness modulus

5. Planks equation

6. Henderson equation

a) P-4, Q-1, R-3, S-2

b) P-5, Q-1, R-4, S-6

c) P-4, Q-5, R-3, S-6

d) P-4, Q-1, R-3, S-6

68. Match the pairs


71/90

68. Match the pairs

Group A Group B

P Roultslaw 1. Describe the freezing of food with some

assumptions

Q Fanningsfactor 2. Describe the drying of solid food withsome assumption

R Stefan boltzman law 3. Prediction of water activity for dilute

binary solution

S Planks equation 4. Estimates the total emissive power of black

body

5. Used for laminar flow condition

6. Used for turbulent flow condition

a) P-3, Q-5, R-4, S-2

b) P-3, Q-6, R-4, S-1

c) P-3, Q-5, R-4, S-1

d) P-3, Q-6, R-4, S-2

69. Match the pairs


72/90

Group A Group B

P Scalping 1. Classification of cleaned product into

quality fraction.

Q Grading 2. Separation of cleaned product into quality

fraction on the basis of size, shape,

texture

R Sorting 3. Removal of foreign and undesirable

matters.

S Cleaning 4. Separation of stones from paddy.

5. Removal of few large particles in an

initial process.

a) P-5, Q-1, R-2, S-3

b) P-5, Q-2, R-1, S-3

c) P-4, Q-1, R-2, S-3

d) P-4, Q-2, R-1, S-3

70.Match the pairs


73/90

Group A Group B

P Killing of vegetative

microorganism

1 Sterilization

Q Killing of heat resistant pores 2 Pasteurization

R Thermal Death Time (TDT)

curve

3 Temperature Vs log (time)

S Raults law 4 Time Vs temperature

5 Water activity

a) P2 , Q1 , R4 , S5

b) P1 , Q2 , R5, S4

c) P2 , Q1 , R3 , S5

d) P5 , Q4 , R1 , S3

Q 71: Given sample of 250 gm After shaking a


74/90

Q. 71: Given sample of 250 gm. After shaking a

sieve set for 5 min. The weight obtained on

different sieves are as follows.

Mesh 3/8 4 8 14 28 48 100 Pan

Weight of sample

(gm)

0 0 10 15 65 100 60 0

The average particle diameter of ground sample is

________.a) 0.1 mm b) 0.2 mm

c) 0.25 mm d) 0.50 mm

Q 72 : Given sample of 250 gm After shaking a sieve


75/90

Q. 72 : Given sample of 250 gm. After shaking a sieve

set for 5 min. The weight obtained on different sieves

are as follows.

Mesh 3/8 4 8 14 28 48 100 Pan

Weight of sample

(gm)

0 0 10 15 65 100 60 0

Estimate the uniformity index for the sieves

sample _________

a) 2 : 4 : 4 b) 0 : 3 : 7

c) 1 : 4 : 5 d) 2 : 5 : 3


76/90

Q.73 In a wheat milling experiment it was found that

to grind 4.33 mm sized grains to IS sieve 35 (0.351

mm opening), the power requirement was 8 kw. Feedrate of milling is 200 kg / hr. Calculate the power

requirement for milling of wheat by same mill to IS

sieve 15 (0.157 mm) using Rittingers law.

a) 8 kw

b) 10.56 kwc) 18.75 kw

d) None of these


77/90

Q.74 In a wheat milling experiment it was found that

to grind 4.33 mm sized grains to IS sieve 35 (0.351

mm opening), the power requirement was 8 kw. Feedrate of milling is 200 kg / hr. Calculate the power

requirement for milling of wheat by same mill to IS

sieve 15 (0.157 mm) using kicks law.

a) 8 kw

b) 10.56 kwc) 18.75 kw

d) 15.275 kw

Q. 75: In pigeon pea milling experiment with concentric


78/90

Q. 75: In pigeon pea milling experiment with concentric

cylinder abrasive will the following observation were

made.

i) Amount of unhulled grains = 2.5%ii) Recovery of whole split kernels after milling = 71.4 %

iii) Amount of crushed kernels = 3.6 %

iv) Amount of power husk removed = 11.5 %

v) The cotyledon to grain ratio of grain was 86.5

Milling efficiency of the system kupritz formula is _____.

a) 73.23 %b) 71.4 %

c) 68.5 %

d) 62.72 %


79/90

Group III

(Linked answer questions)

Question No. 76 to 85 will carry two mark

each


80/90

Q. 76 The air flow through a grain bed of 10 cm thick

with superficial velocity is 2 m/min. The grains arespherical with 1200 kg/m3true density and 800 kg/m3

bulk density. The density and viscosity of the air are

1.2 kg/m3and 1.85 x 10-5PaS respectively . Theporosity of the grain bed is _____

a. 33.33 % b. 50.00 %c. 66.66 % d. 75.00%


81/90

Q.77: The air flow through a grain bed of 10 cm thick

with superficial velocity is 2 m/min. The grains arespherical with 1200 kg/m3true density and 800 kg/m3

bulk density. The density and viscosity of the air are

1.2 kg/m3and 1.85 x 10-5PaS respectively. The staticpressure drop in air flowing a grain bed is _____

a. 1177.20 Pa b. 1176.02 Pac. 788.72 Pa d. 787.94 Pa


82/90

Q.78 One kilogram of an air stream (A) at 300C and 90%

relative humidity is mixed with 2 kg of air stream (B) at 300

Chaving absolute humidity of 0.0103 kg/kg of dry air. The

mixture is then heated to 600C .The saturation vapour pressure

of water at 300C and 600C are 4.11 and 11.90 kPa

respectively. Total pressure of the system is 101.325 kPa.Average molecular weight of air is 29 kg/kmol. The absolute

humidity of mixed air stream is __________.

a. 0.0103 kg/kg of dry air b. 0.0147 kg/kg of dry airc. 0.0236 kg/kg of dry air d. 0.0206 kg/kg of dry air


83/90

Q.79: One kilogram of an air stream (A) at 300C and 90%

relative humidity is mixed with 2 kg of air stream (B) at 300

Chaving absolute humidity of 0.0103 kg/kg of dry air. The

mixture is then heated to 600C .The saturation vapour pressure

of water at 300C and 600C are 4.11 and 11.90 kPa

respectively. Total pressure of the system is 101.325 kPa.Average molecular weight of air is 29 kg/kmol. The relative

humidity of mixed air stream is __________.

a. 11.75 % b. 25.55 %c. 52.50 % d. 90.00 %


84/90

Q. 80 In sieve analysis of corn grits with respect to

any particular screen opening the mass fraction of

desired particle size in feed, overflow & underflowstreams are 0.47, 0.85 and 0.20 respectively. The feed

rate of material on the screen is 10 kg / hr. The mass

flow rate for the overflow stream is _______.

a) 4.15 kg / hr

b) 5.85 kg / hrc) 6.00 kg / hr

d) 7.11 kg / hr

80


85/90

Q. 81 In sieve analysis of corn grits with respect to

any particular screen opening the mass fraction of

desired particle size in feed, overflow & underflowstreams are 0.47, 0.85 and 0.20 respectively. The feed

rate of material on the screen is 10 kg / hr. The overall

effectiveness of the screen is _________.

a) 0.462

b) 0.562c) 0.662

d) 0.762


86/90

Q. 82 : In dryer 4 tonnes sorghum (final weight) is

dried from 18 % (d.b.) moisture content to 13 % (d.b.)

moisture content per hour. Given thatDryer efficiency = 50 %

Latent heat of evaporation = 574 kcal / kg

Amount of moisture to be removed to _______.

a) 144 kg

b) 244 kgc) 344 kg

d) 444 kg

Q. 83: In dryer 4 tonnes sorghum (final weight) is


87/90

Q. 83: In dryer 4 tonnes sorghum (final weight) is

dried from 18 % (d.b.) moisture content to 13 % (d.b.)

moisture content per hour. Given thatDryer efficiency = 50 %

Latent heat of evaporation = 574 kcal / kg

Calculate the amount of heat requirement for drying is

_________

a) 574 kcal /hr

b) 140056 kcal / hrc) 280112 kcal / hr

d) 560224 kcal / hr

Q.84 A thick walled tube of stainless steel (A) having


88/90

Q.84 A thick walled tube of stainless steel (A) having

thermal conductivity k= 16 W/mK and dimensions of

0.0254 m ID and 0.0508 m OD is covered with0.0254m layer of asbestos (B) having thermal

conductivity, k=0.025 WmK. The inside wall

temperature of the pipe is 1500C and the outside

surface of the insulation is at 300C.

The log mean area (AlmA) for stainless steel tube is

_________.

a. 0.1151 m2 b. 0.1242 m2

c. 0.2303 m2 d. 0.3454 m2

Q. 85 A thick walled tube of stainless steel (A) having


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Q. 85 A thick walled tube of stainless steel (A) having

thermal conductivity k= 16 W/mK and dimensions of

0.0254 m ID and 0.0508 m OD is covered with0.0254m layer of asbestos (B) having thermal

conductivity, k=0.025 WmK. The inside wall

temperature of the pipe is 1500C and the outside

surface of the insulation is at 300C.

The heat loss per meter length of the pipe is

_____________.

a. 54.32 W b. 54.32 kW

c. 27.16 W d. 27.16 kW


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agriculture engg. and science

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