The volume of a solid rubber ball when it is carried from the surface to the bottom of a 200 m deep lake decreases by 0.1%. The value for bulk modulus of elasticity for rubber will be :

(A)

2 x 10^{9} pascal

(B)

2 x 10^{6} pascal

(C)

2 x 10^{4} pascal

(D)

2 x 10^{7} pascal

Question-2

Two rods of different materials having coefficients of linear expansion α_{1 }and α_{2} , Young's modulii Y_{1} and Y_{2 }respectively are fixed between two rigid massive walls. The rods are heated such that they undergo the same increase in temperature. There is no bending of rods. If α_{1} : α_{2} =2 : 3, the thermal stresses developed in the two rods are equal provided Y_{1} : Y_{2} is equal to :

(A)

2 : 3

(B)

1 : 1

(C)

3 : 2

(D)

4 : 9

Question-3

A wire of density 9 gm/cm^{3} is stretched and clamped between two clamps distant 100 cm apart by a force which produces an elongation of 0.05 cm in it. If Y = 9 x 10^{11} dyne/cm^{2} then the minimum frequency of transverse vibrations will be :

(A)

15.15 per sec

(B)

25.25 per sec

(C)

35.35 per sec

(D)

53.53 per sec

Question-4

A bridge can bear 4 x 10^{4} kg weight. If the breaking stress is 47 x 10^{3} N/m^{3} and factor of safety is 5 then the area of cross section of the rod will be :^{ }

(A)

4.34 m^{2}

(B)

43.4 m^{2}

(C)

0.434 m^{2}

(D)

0.04 m^{2}

Question-5

A metal block is experencing an atmospheric pressure of 10^{5} N/m^{2}. When the same block is placed in a vaccum chamber, the fractional change in its volume : (the bulk modulus of metal is 1.25 x 10^{11} N/m^{2})

(A)

8 x 10^{-7}

(B)

1 x 10^{-7}

(C)

4 x 10^{-7}

(D)

2 x 10^{-7}

Question-6

The Poisson's ratio for a material is 0.1. If the longitudinal strain of a rod of this material is 1 x 10^{-3}, then the percentage change in the volume of rod will be :

(A)

8%

(B)

0.8%

(C)

0.08%

(D)

0.008%

Question-7

Young's modulus of the material of a wire of length L and radius r is Y N/m^{2}. If the length is reduced to ^{L}/_{2} and radius to ^{r}/_{2}, the Young's modulus will be :

(A)

Y/4

(B)

Y/2

(C)

Y

(D)

2Y

Question-8

A force of 200 N is applied at one end of a wire of length 2 m and having area of cross-section 10^{-2} cm^{2}. The other end of the wire is rigidly fixed. It coefficient of linear expansion of the wire α = 8 x 10^{-6}/^{o}C and Young's modulus Y = 2.2 x 10^{11} N/m^{2} and its temperature is increased by 5^{o}C, then the increase in the tension of the wire will be :

(A)

2.4 N

(B)

8.8 N

(C)

4.2 N

(D)

4.4 N

Question-9

A thick rope of density 'ρ' and length 'L' is hung from a rigid support. The Young's modulus of the material of rope is 'Y'. The increase in length of the rope due to its own weight is :

(A)

1/4 ρgL^{2}/Y

(B)

1/2 ρgL^{2}/Y

(C)

ρ gL^{2}/Y

(D)

ρ gL/Y

Question-10

The Young's modulus of a wire is Y. If the energy per unit volume is E, then the strain will be :

(A)

EY

(B)

E/Y

(C)

(D)

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