78. Pick up the correct statement from the following :

A. The moment of inertia is calculated about the axis about which bending takes place

B. If tensile stress is less than axial stress, the section experiences compressive stress

C. If tensile stress is equal to axial stress, the section experiences compressive stress

D. All the above.

79. The ratio of the area of cross-section of a circular section to the area of its core, is

A.4

B.8

C.12

D.16

80. The eccentricity (e) of a hollow circular column, external diameter 25 cm, internal diameter 15 cm for an eccentric load 100 t for non-development of tension, is

A. 2.75 cm

B. 3.00 cm

C. 3.50 cm

D. 4.25 cm

81. Co-efficient of wind resistance of a circular surface, is 21.146. Pick up the correct statement from the following :

A. The structural member subjected to compression and whose dimensions are small as compared to its length, is called a strut

B. The vertical compression members, are generally known as columns or stanchions

C. Deflection in lateral direction of a long column, is generally known as buckling

D. All the above.

82. A masonry dam (density = 20,000 N/m3) 6 m high, one metre wide at the top and 4 m wide at the base, has vertical water face. The minimum stress at the base of the dam when the reservoir is full, will be

A. 75 N/m2

B. 750 N/m2

C. 7500 N/m2

D. 75000 N/m2,

83. Slenderness ratio of a long column, is

A. area of cross-section divided by radius of gyration

B. area of cross-section divided by least radius of gyration

C. radius of gyration divided by area of cross-section

D. length of column divided by least radius of gyration.

84. P =n2E1 is the equation for Euler's crippling load if L2

A. both the ends are fixed

B. both the ends are hinged

C. one end is fixed and other end is free

D. one end is fixed and other end is hinged.

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