Properties of Solids & Fluids · JEE Main previous year questions

2021 11 questions

1. Q342021 · 26 Aug 2021 · Shift 2

   A cylindrical container of volume $4.0\times 10^{-3}{\text{ m}}^3$ contains one mole of hydrogen and two moles of carbon dioxide. Assume the temperature of the mixture is $400\text{ K}$. The pressure of the mixture of gases is : [Take gas constant as $8.3{\text{ J mol}}^{-1}{\text{ K}}^{-1}$]

   1. A.$249\times 10^1\text{ Pa}$
   2. B.$24.9\times 10^3\text{ Pa}$
   3. C.$24.9\times 10^5\text{ Pa}$
   4. D.$24.9\text{ Pa}$
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   Answer: C

2. Q332021 · 27 Jul 2021 · Shift 2

   A raindrop with radius R = 0.2 mm falls from a cloud at a height h = 2000 m above the ground. Assume that the drop is spherical throughout its fall and the force of buoyance may be neglected, then the terminal speed attained by the raindrop is : [Density of water $f_w=1000\mathrm{kg}{\mathrm{m}}^{-3}$ and Density of air $f_a=1.2\mathrm{kg}{\mathrm{m}}^{-3}$, g = $10m/{\mathrm{s}}^2$, Coefficient of viscosity of air = $1.8\times 10^{-5}\mathrm{Ns}{\mathrm{m}}^{-2}$]

   1. A.$250.6\mathrm{m}{\mathrm{s}}^{-1}$
   2. B.$43.56\mathrm{m}{\mathrm{s}}^{-1}$
   3. C.$4.94\mathrm{m}{\mathrm{s}}^{-1}$
   4. D.$14.4\mathrm{m}{\mathrm{s}}^{-1}$
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   Answer: C

3. Q402021 · 25 Jul 2021 · Shift 1

   Two wires of same length and radius are joined end to end and loaded. The Young's moduli of the materials of the two wires are $Y_1$ and $Y_2$. The combination behaves as a single wire then its Young's modulus is :

   1. A.$Y=\frac{2Y_1{Y}_2}{3(Y_1+Y_2)}$
   2. B.$Y=\frac{2Y_1{Y}_2}{Y_1+Y_2}$
   3. C.$Y=\frac{Y_1{Y}_2}{2(Y_1+Y_2)}$
   4. D.$Y=\frac{Y_1{Y}_2}{Y_1+Y_2}$
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   Answer: B

4. Q582021 · 22 Jul 2021 · Shift 2· Numerical answer

   The area of cross-section of a railway track is $0.01{\text{ m}}^2$. The temperature variation is $10^{\circ }\text{C}$. Coefficient of linear expansion of material of track is $10^{-5}{/}^{\circ }\text{C}$. The energy stored per meter in the track is ________ J/m. (Young's modulus of material of track is $10^{11}{\text{ Nm}}^{-2}$)

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   Answer: 5

5. Q352021 · 20 Jul 2021 · Shift 1

   Consider a mixture of gas molecule of types A, B and C having masses $m_A<m_B<m_C$. The ratio of their root mean square speeds at normal temperature and pressure is :

   1. A.$v_A=v_B\ne v_C$
   2. B.$\frac{1}{v_A}>\frac{1}{v_B}>\frac{1}{v_C}$
   3. C.$\frac{1}{v_A}<\frac{1}{v_B}<\frac{1}{v_C}$
   4. D.$v_A=v_B=v_C=0$
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   Answer: C

6. Q312021 · 16 Mar 2021 · Shift 1

   The pressure acting on a submarine is $3\times 10^5\mathrm{Pa}$ at a certain depth. If the depth is doubled, the percentage increase in the pressure acting on the submarine would be : (Assume that atmospheric pressure is $1\times 10^5\mathrm{Pa}$ and density of water is $10^3\mathrm{kg}{\mathrm{m}}^{-3}$, $\mathrm{g}=10\mathrm{m}{\mathrm{s}}^{-2}$)

   1. A.$\frac{200}{5}\%$
   2. B.$\frac{200}{3}\%$
   3. C.$\frac{3}{200}\%$
   4. D.$\frac{5}{200}\%$
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   Answer: B

7. Q482021 · 16 Mar 2021 · Shift 1

   The volume V of an enclosure contains a mixture of three gases, 16 g of oxygen, 28 g of nitrogen and 44 g of carbon dioxide at absolute temperature T. Consider R as universal gas constant. The pressure of the mixture of gases is :

   1. A.$\frac{3RT}{V}$
   2. B.$\frac{4RT}{V}$
   3. C.$\frac{88RT}{V}$
   4. D.$\frac{5}{2}\frac{RT}{V}$
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   Answer: D

8. Q342021 · 26 Feb 2021 · Shift 1

   A large number of water drops, each of radius r, combine to have a drop of radius R. If the surface tension is T and mechanical equivalent of heat is J, the rise in heat energy per unit volume will be :

   1. A.$\frac{2T}{J}\left(\frac{1}{r}-\frac{1}{R}\right)$
   2. B.$\frac{3T}{J}\left(\frac{1}{r}-\frac{1}{R}\right)$
   3. C.$\frac{3T}{rJ}$
   4. D.$\frac{2T}{rJ}$
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   Answer: B

9. Q472021 · 26 Feb 2021 · Shift 1

   The normal density of a material is $\rho$ and its bulk modulus of elasticity is K. The magnitude of increase in density of material, when a pressure P is applied uniformly on all sides, will be :

   1. A.$\frac{\rho K}{P}$
   2. B.$\frac{PK}{\rho }$
   3. C.$\frac{\rho P}{K}$
   4. D.$\frac{K}{\rho P}$
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   Answer: C

10. Q572021 · 26 Feb 2021 · Shift 1· Numerical answer

    A container is divided into two chambers by a partition. The volume of first chamber is 4.5 litre and second chamber is 5.5 litre. The first chamber contain 3.0 moles of gas at pressure 2.0 atm and second chamber contain 4.0 moles of gas at pressure 3.0 atm. After the partition is removed and the mixture attains equilibrium, then, the common equilibrium pressure existing in the mixture is $x\times 10^{-1}\mathrm{atm}$. Value of x is _________.

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    Answer: 25

11. Q402021 · 26 Feb 2021 · Shift 2

    The internal energy (U), pressure (P) and volume (V) of an ideal gas are related as $U=3PV+4$. The gas is :

    1. A.either monoatomic or diatomic.
    2. B.monoatomic only.
    3. C.polyatomic only.
    4. D.diatomic only.
    Show answer

    Answer: C