8. A material is said to be perfectly elastic if

A. it regains its original shape on removal of the load

B. It regains its original shape partially on removal of the load

C. it does not regain its original shape at all

D. none of these.

9. At yield point of a test piece, the material

A. obeys Hooke's law

B. behaves in an elastic manner

C. regains its original shape on removal of the load

D. undergoes plastic deformation,

10. The ratio of lateral strain to axial strain of a homogeneous material, is known

A. Yield ratio

B. Hooke's ratio

C. Poisson's ratio

D. Plastic ratio.

11. A compound bar consists of two bars of equal length. Steel bar cross-section is 3500 mm2 and that of brass bar is 3000 mm2, These are subjected to a compressive load 100,000 N. If Eb = 0.2 MN/mm2 and Eb = 0.1 MN/mm2, the stresses developed are :

A. o, = 10 N/mm2, a = 20 N/mm2

B. o, = 8 N/mm2, os = 16 N/mm2

C. a, = 6 N/mm2_, as = 12 N/mm2

D. b = 5 N/mm2, os = 10 N/mm2,

12. If a concrete column 200 x 200 mm in cross-section is reinforced with four steel bars of 1200 mm2 total cross-sectional area. Calculate the safe load for the column if permissible stress in concrete is 5 N/mm2 and Es is 15 E,

A. 264 MN

B. 274 MN

C. 284 MN

D. 294 MN

13. Two bars, one of steel and the other of copper having areas of cross-sections As and A,, coefficient of expansion as

A. 8 = Lt x (cceE Ac ? s E sAs) EA + EsAs

B.Lt + (lac E cAe asE As) E,A, + E

C. 8 = Lt(cce-EcAc asEsAs)

D. 8 = Lt x(cteE + sE sAs) ? E

14. A steel rod of sectional area 250 sq. mm connects two parallel walls 5 m apart. The nuts at the ends were tightened when the rod was heated to 100?C. Rusted = 0.000012/C?, E steel = 0.2 MN/mm2, the tensile force developed at a temperature of 50?C, is

A. 80 N/mm2

B. 100 N/mm2

C. 120 N/mm2

D. 150 N/mm2.

Page **2** of **16**