Q 1 :    

If average depth of an ocean is 4000m and the bulk modulus of water is 2×109 Nm-2, then fractional compression VV of water at the bottom of ocean is α×10-2. The value of α is ______ .(Given, g=10ms-2,ρ=1000kg m-3)                      [2024]



(2)        B=ΔP(ΔVV)

            -(ΔVV)=ρghB=1000×10×40002×109

            =2×10-2[-ve sign represents compression]

 



Q 2 :    

The depth below the surface of sea to which a rubber ball be taken so as to decrease its volume by 0.02% is ______ m.    

(Take density of sea water=103kgm-3,Bulk modulus of rubber=9×108Nm-2,and g=10ms-2)                      [2024]



(18)      β=-ΔPΔVVΔP=-βΔVV 

            ρgh=-βΔVV

           103×10×h=-9×108×(-0.02100)h=18m

 



Q 3 :    

Match List-I with List-II

  List - I   List - II
A A force that restores an elastic body of unit area to its original state (I) Bulk modulus
B Two equal and opposite forces parallel to opposite faces (II) Young’s modulus
C Forces perpendicular everywhere to the surface per unit area same everywhere (III) Stress
D Two equal and opposite forces perpendicular to opposite faces (IV) Shear modulus

 

Choose the correct answer from the options given below:                      [2024]

  • (A)-(III), (B)-(IV), (C)-(I), (D)-(II)

     

  • (A)-(II), (B)-(IV), (C)-(I), (D)-(III)

     

  • (A)-(IV), (B)-(II), (C)-(III), (D)-(I)

     

  • (A)-(III), (B)-(I), (C)-(II), (D)-(IV)

     

(1)

 



Q 4 :    

The fractional compression (VV) of water at the depth of 2.5 km below the sea level is _____%. Given, the Bulk modulus of water = 2×109 Nm2, density of water =103 kg m3, acceleration due to gravity g = 10 ms2.          [2025]

  • 1.75

     

  • 1.0

     

  • 1.5

     

  • 1.25

     

(4)

B=P(VV)

 (VV)=PB=ρghB

                               =103×10×2.5×1032×109=1.25%



Q 5 :    

A cylindrical rod of length 1 m and radius 4 cm is mounted vertically. It is subjected to a shear force of 105 N at the top. Considering infinitesimally small displacement in the upper edge, the angular displacement θ of the rod axis from its original position would be: (shear moduli, G=1010 N/m2)          [2025]

  • 1/160 π

     

  • 1/4 π

     

  • 1/40 π

     

  • 1/2 π

     

(1)

σshear=FA=ηθ

Shear moduli = σshearθ

1010=105π×16×104×1θ

θ=1160πRadian



Q 6 :    

The increase in pressure required to decrease the volume of a water sample by 0.2% is P×105 Nm2. Bulk modulus of water is 2.15×109 Nm2. The value of P is __________.          [2025]



(43)

Since bulk modulus is given as

B=P(VV)

2.15×109=P(0.2100)

P=2.15×109×2×103=4.3×106=43×105 N/m2



Q 7 :    

The volume contraction of a solid copper cube of edge length 10 cm, when subjected to a hydraulic pressure of 7×106Pa, would be _______ mm3.   

(Given bulk modulus of copper = 1.4×1011 Nm-2)                     [2025]



(50)

B=PVV=VPV

 V=VPB=(100 mm)3×7×106Pa1.4×1011N/m2=50 mm3

 |V|=50 mm3



Q 8 :    

Two slabs with square cross section of different materials (1, 2) with equal sides (l) and thickness d1 and d2 such that d2=2d1 and l>d2. Considering lower edges of these slabs are fixed to the floor, we apply equal shearing force on the narrow faces. The angle of deformation is θ2=2θ1. If the shear moduli of material 1 is 4×109N/m2, then shear moduli of material 2 is x×109N/m2, where value of x is __________.           [2025]



(1)

Deformation angle

2θ1=θ2  2σ1η1=σ2η2

 2(FA1η1)=FA2η2

 2(Fld1η1)=Fld2η2

 η2=η14=1×109  x=1



Q 9 :    

A sample of a liquid is kept at 1 atm. It is compressed to 5 atm which leads to change of volume of 0.8 cm3. If the bulk modulus of the liquid is 2 GPa, the initial volume of the liquid was ______ litre. (Take 1 atm = 105Pa)          [2025]



(4)

Given, Initial pressure of liquid (Pi) = 1 atm Final pressure of liquid (Pf) = 5 atm.

Change in pressure (dP) = PfPi= 4 atm = 4×105Pa

Change in volume (dV) = – 0.8 cm3

Bulk modulus (B) = 2×109Pa

Now, B=dP(dV/V)  V=B(dVdP)

 V=2×109×(0.8×106)4×105

               =4×103m3=4 litre