Properties of Solids & Fluids · JEE Main previous year questions

2019 16 questions

1. Q492019 · 12 Apr 2019 · Shift 1

   At $40^{\circ }\text{C}$, a brass wire of 1 mm radius is hung from the ceiling. A small mass, M is hung from the free end of the wire. When the wire is cooled down from $40^{\circ }\text{C}$ to $20^{\circ }\text{C}$ it regains its original length of 0.2 m. The value of M is close to : (Coefficient of linear expansion and Young's modulus of brass are $10^{-5}{\text{ /}}^{\circ }\text{C}$ and $10^{11}{\text{ N/m}}^2$, respectively; $g=10{\text{ ms}}^{-2}$)

   1. A.1.5 kg
   2. B.0.5 kg
   3. C.9 kg
   4. D.0.9 kg
   Show answer

   Answer: C

2. Q422019 · 12 Apr 2019 · Shift 2

   A diatomic gas with rigid molecules does 10 J of work when expanded at constant pressure. What would be the heat energy absorbed by the gas, in this process ?

   1. A.35 J
   2. B.30 J
   3. C.25 J
   4. D.40 J
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   Answer: A

3. Q452019 · 12 Apr 2019 · Shift 2

   A solid sphere, of radius R acquires a terminal velocity $v_1$ when falling (due to gravity) through a viscous fluid having a coefficient of viscosity. The sphere is broken into 27 identical solid spheres. If each of these spheres acquires a terminal velocity, $v_2$, when falling through the same fluid, the ratio $(v_1/v_2)$ equals :

   1. A.$\frac{1}{9}$
   2. B.$\frac{1}{27}$
   3. C.27
   4. D.9
   Show answer

   Answer: D

4. Q532019 · 10 Apr 2019 · Shift 1

   The ratio of surface tensions of mercury and water is given to be 7.5 while the ratio of their densities is 13.6. Their contact angles, with glass, are close to $135^{\circ }$ and $0^{\circ }$, respectively. It is observed that mercury gets depressed by an amount h in a capillary tube of radius ${\mathrm{r}}_1$, while water rises by the same amount h in a capillary tube of radius ${\mathrm{r}}_2$. The ratio, $({\mathrm{r}}_1/{\mathrm{r}}_2)$, is then close to :

   1. A.2/5
   2. B.2/3
   3. C.3/5
   4. D.4/5
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   Answer: A

5. Q382019 · 10 Apr 2019 · Shift 2

   One mole of ideal gas passes through a process where pressure and volume obey the relation $P=P_0\left[1-\frac{1}{2}{\left(\frac{V_0}{V}\right)}^2\right]$. Here ${\mathrm{P}}_0$ and ${\mathrm{V}}_0$ are constants. Calculate the change in the temperature of the gas if its volume changes form ${\mathrm{V}}_0$ to $2{\mathrm{V}}_0$

   1. A.$\frac{3}{4}\frac{P_0{V}_0}{R}$
   2. B.$\frac{1}{2}\frac{P_0{V}_0}{R}$
   3. C.$\frac{5}{4}\frac{P_0{V}_0}{R}$
   4. D.$\frac{1}{4}\frac{P_0{V}_0}{R}$
   Show answer

   Answer: C

6. Q392019 · 10 Apr 2019 · Shift 2

   Water from a tap emerges vertically downwards with an initial speed of $1.0\mathrm{m}{\mathrm{s}}^{-1}$ . The cross-sectional area of the tap is $10^{-4}{\mathrm{m}}^2$. Assume that the pressure is constant throughout the stream of water and that the flow is streamlined. The cross-sectional area of the stream, 0.15 m below the tap would be : (Take $g=10\mathrm{m}{\mathrm{s}}^{-2}$)

   1. A.$5\times 10^{-4}{\mathrm{m}}^2$
   2. B.$2\times 10^{-5}{\mathrm{m}}^2$
   3. C.$5\times 10^{-5}{\mathrm{m}}^2$
   4. D.$1\times 10^{-5}{\mathrm{m}}^2$
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   Answer: C

7. Q412019 · 10 Apr 2019 · Shift 2

   A submarine experiences a pressure of $5.05\times 10^6\mathrm{Pa}$ at a depth of ${\mathrm{d}}_1$ in a sea. When it goes further to a depth of ${\mathrm{d}}_2$, it experiences a pressure of $8.08\times 10^6\mathrm{Pa}$. Then ${\mathrm{d}}_2-{\mathrm{d}}_1$ is approximately (density of water $=10^{3}kg/{\mathrm{m}}^3$ and acceleration due to gravity $=10\mathrm{m}{\mathrm{s}}^{-2}$ ) :

   1. A.600 m
   2. B.400 m
   3. C.300 m
   4. D.500 m
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   Answer: C

8. Q522019 · 10 Apr 2019 · Shift 2

   In an experiment, brass and steel wires of length 1 m each with areas of cross section $1\mathrm{m}{\mathrm{m}}^2$ are used. The wires are connected in series and one end of the combined wire is connected to a rigid support and other end is subjected to elongation. The stress required to produce a net elongation of 0.2 mm is, [Given, the Young's Modulus for steel and brass are, respectively, $120\times 10^{9}N/{\mathrm{m}}^2$ and $60\times 10^{9}N/{\mathrm{m}}^2$]

   1. A.$8.0\times 10^{6}N/{\mathrm{m}}^2$
   2. B.$1.2\times 10^{6}N/{\mathrm{m}}^2$
   3. C.$0.2\times 10^{6}N/{\mathrm{m}}^2$
   4. D.$1.8\times 10^{6}N/{\mathrm{m}}^2$
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   Answer: A

9. Q552019 · 10 Apr 2019 · Shift 2

   A cubical block of side 0.5 m floats on water with 30% of its volume under water. What is the maximum weight that can be put on the block without fully submerging it under water? [Take, density of water = $10^{3}kg/{\mathrm{m}}^3$]

   1. A.30.1 kg
   2. B.87.5 kg
   3. C.65.4 kg
   4. D.46.3 kg
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   Answer: B

10. Q572019 · 10 Apr 2019 · Shift 2

    When heat Q is supplied to a diatomic gas of rigid molecules, at constant volume its temperature increases by $\Delta \mathrm{T}$. the heat required to produce the same change in temperature, at a constant pressure is :

    1. A.$\frac{7}{5}Q$
    2. B.$\frac{3}{2}Q$
    3. C.$\frac{2}{3}Q$
    4. D.$\frac{5}{3}Q$
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    Answer: A

11. Q532019 · 9 Apr 2019 · Shift 1

    If 'M' is the mass of water that rises in a capillary tube of radius 'r', then mass of water which will rise in a capillary tube of radius '2r' is :

    1. A.M
    2. B.4M
    3. C.M/2
    4. D.2M
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    Answer: D

12. Q512019 · 9 Apr 2019 · Shift 2

    A wooden block floating in a bucket of water has 4/5 of its volume submerged. When certain amount of an oil is poured into the bucket, it is found that the block is just under the oil surface with half of its volume under water and half in oil. The density of oil relative to that of water is :-

    1. A.0.8
    2. B.0.7
    3. C.0.6
    4. D.0.5
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    Answer: C

13. Q332019 · 12 Jan 2019 · Shift 1

    An ideal gas occupies a volume of $2{\mathrm{m}}^3$ at a pressure of $3\times 10^6\mathrm{Pa}$. The energy of the gas is :

    1. A.$6\times 10^4\mathrm{J}$
    2. B.$9\times 10^6\mathrm{J}$
    3. C.$3\times 10^2\mathrm{J}$
    4. D.$10^8\mathrm{J}$
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    Answer: B

14. Q422019 · 12 Jan 2019 · Shift 2

    A load of mass M kg is suspended from a steel wire of length 2m and radius 1.0 mm in Searle's apparatus experiment. The increase in length produced in the wire is 4.0 mm. Now the load is fully immersed in a liquid of relative density 2. The relative density of the material of load is 8. The new value of increase in length of the steel wire is:

    1. A.5.0 mm
    2. B.zero
    3. C.3.0 mm
    4. D.4.0 mm
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    Answer: C

15. Q512019 · 12 Jan 2019 · Shift 2
    
    1. A.
    2. B.
    3. C.
    4. D.
    Show answer

    Answer: B

16. Q562019 · 9 Jan 2019 · Shift 1

    Drift speed of electrons, when $1.5\text{ A}$ of current flows in a copper wire of cross section $5{\text{ mm}}^2$, is $v$. If the electron density in copper is $9\times 10^{28}/{\text{m}}^3$ the value of $v$ in mm/s is close to (Take charge of electron to be $=1.6\times 10^{-19}\text{C}$)

    1. A.0.02
    2. B.3
    3. C.2
    4. D.0.2
    Show answer

    Answer: A