78. The seepage exit gradient in a soil is the ratio of

A. total head to the length of seepage

B. flow line to slope

C. head upstream to that at downstream

D. head loss to the length of the seepage

79. The critical exist gradient of seepage water in soils, increases with

A. an increase in specific gravity

B. a decrease in specific gravity

C. a decrease in void ratio

D. both (a) and (c)

80. The critical exist gradient of seepage water in soils, is

A. directly proportional to the voids ratio

B. inversely proportional to the specific gravity

C. directly proportional to the specific gravity

D. none of these.

81. In a fow net

A. flow lines and equipotential lines cross each other at right angles

B. fields are rectangles whose length is twice the breadth

C. smaller the dimensions of the field, smaller will be the hydraulic gradient and velocity of now through it

D. for homogeneous soil, the curves are smooth and circular.

82. A flow net may be utilised for the determination of

A. exit gradient

B. seepage

C. hydrostatic pressure

D. seepage pressure

83. A phreatic line is defined as the line within a dam section below which there are

A. positive equipotential lines

B. positive hydrostatic pressure

C. negative hydrostatic pressure

D. negative equipotential lines

84. The phreatic line in an earth dam may be

A. circular

B. elliptical

C. parabolic

D. a straight line

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