18 Which of the following has the least elasticity :
a) Rubber b) Steel c) Copper d) Iron
19 A rectangular beam is bent into the arc of a circle , the strain produced in the beam is :
a) Extensional only b) Compressional only c) Both d) Shearing
20 Young’s modulus of the material of a wire of length L and radius r is Y N/m2. If the length is
reduced to L/2 and radius to r/2 , the Young’s modulus will be
a) Y b) 2y c) Y/4 d) Y/2
21 The Young’s modulus for a liquid is : a) 0 b) 1 c) ¥ d) Some finit , non zero constant
22 Poisson’s ratio is the ratio between:
a) Lateral contraction per unit stress and longitudinal elongation per unit stress
b)Y and h c) Y and K d) K and h
23 The Young’s modulus of brass and steel are 10 X1010 N/m2 and 20 X 1010N/m2 respectively.
A brass wire and a steel wire of the same length are extended by 1mm under the same force, the
radii of brass and steel wires are RB and RS respectively.
a) RS = Ö2 RB b) RS = RB/Ö 2 c) RS = 4RB d) RS = RB/4
24 A rectangular beam of width b and depth d is supported symmetriclly on two knife edges distance
L apart and loaded in the middle by a weight w. Then the depression is given by
(Young’s modulus = E)
a) wL3 / 4Ebd3 b) EWL3/ bd3 c) Wd3/ 4EbL3 d) Wbd2/EL3
25 For a given metal , the Young’s modulus is 2.4times that of rigidity modulus. Its poisson’s ratio is
a) 2.4 b)1.2 c) 0.4 d) 0.2
26 A cable is cut to half of its original length. The maximum load that it can support is :
a) Half b)Same as previous c) Double d) One -fourth
27 For a metal Y =7.03 X1010 N/m2 and s = 0.345. The value of h will be :
a) 2.65 X1010N/m2 b)2.42 X1010N/m2 c)5.23 X 1010N/m2 d) 10.19 X 1010 N/m2
28 For silver, Young’s modulus is 7.25 X1010 N/m2 and Bulk modulus is 11 X1010N/m2 Its poisson’s
ratio will be : a) -1 b) 0.5 c) 0.39 d) 0.25
29 Poisson’s ratio for tungsten is 0.295 and its Young’s modulus is 41.0 X1011 N/m2 then its volume
elastic ity will be :
a) 33.3 X1011 N/m2 b) 3.3 X1011N/m2 c) 3.3 X1010 N/m2 d) None of the above
30 If the Young’s modulus of the material is 3 times its modulus of rigidity, then its volume elasticity
will be : a)Zero b) Infinity c) 2 X1010N/m d) 3 X 1010N/m2
31 The elasticity limit for a gas :
a) Exists b) Exists only at absolute zero c) Exists for a perfect gas d) Does not exist
32 If Young’s modulus for a material is zero, then the state of material should be :
a) solid b) Solid but powder c) Gas d) None of the above
33 Which one of the following substances possesses the highest elasticity :
a) Rubber b) Glass c) Steel d) Copper
34 Which one of the following quantities does not have the unit of force per unit area :
a) Stress b) Strain c) Young’s modulus of elasticity d) Pressure
35 Two wires of the same material have lengths in the ratio 1 : 2 and their radii are in the ratio1 : Ö2.
If they are stretched by appplying equal forces, the increas in their lengths will be in the ratio :
a) 2 :Ö 2 b) Ö2 : 2 c) 1 : 1 d) 1 : 2
36 The possible value of Poisson;s ratio :
a) 1 b) 0.9 c) 0.8 d) 0.4