Work, Energy & Power · JEE Main previous year questions

2024 10 questions

1. Q392024 · 9 Apr 2024 · Shift 2

   UV light of $4.13\mathrm{eV}$ is incident on a photosensitive metal surface having work function $3.13\mathrm{eV}$. The maximum kinetic energy of ejected photoelectrons will be:

   1. A.$4.13\mathrm{eV}$
   2. B.$1\mathrm{eV}$
   3. C.$7.26\mathrm{eV}$
   4. D.$3.13\mathrm{eV}$
   Show answer

   Answer: B

2. Q442024 · 9 Apr 2024 · Shift 2

   The temperature of a gas is $-78^{\circ }\mathrm{C}$ and the average translational kinetic energy of its molecules is $\mathrm{K}$. The temperature at which the average translational kinetic energy of the molecules of the same gas becomes $2\mathrm{K}$ is :

   1. A.$-78^{\circ }\mathrm{C}$
   2. B.$127^{\circ }\mathrm{C}$
   3. C.$-39^{\circ }\mathrm{C}$
   4. D.$117^{\circ }\mathrm{C}$
   Show answer

   Answer: D

3. Q552024 · 9 Apr 2024 · Shift 2· Numerical answer

   A force $(3x^2+2x-5)\mathrm{N}$ displaces a body from $x=2\mathrm{m}$ to $x=4\mathrm{m}$. Work done by this force is ____ $\mathrm{J}$.

   Show answer

   Answer: 58

4. Q452024 · 6 Apr 2024 · Shift 2

   A total of $48\mathrm{J}$ heat is given to one mole of helium kept in a cylinder. The temperature of helium increases by $2^{\circ }\mathrm{C}$. The work done by the gas is: Given, $\mathrm{R}=8.3\mathrm{J}{\mathrm{K}}^{-1}\mathrm{mo}{\mathrm{l}}^{-1}$.

   1. A.$23.1\mathrm{J}$
   2. B.$48\mathrm{J}$
   3. C.$24.9\mathrm{J}$
   4. D.$72.9\mathrm{J}$
   Show answer

   Answer: A

5. Q382024 · 4 Apr 2024 · Shift 2

   Given below are two statements: one is labelled as Assertion $\mathbf{A}$ and the other is labelled as Reason $\mathbf{R}$. Assertion A: Number of photons increases with increase in frequency of light. Reason R: Maximum kinetic energy of emitted electrons increases with the frequency of incident radiation. In the light of the above statements, choose the most appropriate answer from the options given below:

   1. A.$\mathbf{A}$ is not correct but $\mathbf{R}$ is correct.
   2. B.$\mathbf{A}$ is correct but $\mathbf{R}$ is not correct.
   3. C.Both $\mathbf{A}$ and $\mathbf{R}$ are correct and $\mathbf{R}$ is the correct explanation of $\mathbf{A}$.
   4. D.Both $\mathbf{A}$ and $\mathbf{R}$ are correct and $\mathbf{R}$ is NOT the correct explanation of $\mathbf{A}$.
   Show answer

   Answer: A

6. Q462024 · 1 Feb 2024 · Shift 1

   The pressure and volume of an ideal gas are related as $\mathrm{P}{\mathrm{V}}^{\frac{3}{2}}=\mathrm{K}$ (Constant). The work done when the gas is taken from state $A\left(P_1,V_1,T_1\right)$ to state $B\left(P_2,V_2,T_2\right)$ is :

   1. A.$2\left({\mathrm{P}}_2\sqrt{{\mathrm{V}}_2}-{\mathrm{P}}_1\sqrt{{\mathrm{V}}_1}\right)$
   2. B.$2\left(\sqrt{{\mathrm{P}}_1}{\mathrm{V}}_1-\sqrt{{\mathrm{P}}_2}{\mathrm{V}}_2\right)$
   3. C.$2\left({\mathrm{P}}_2{\mathrm{V}}_2-{\mathrm{P}}_1{\mathrm{V}}_1\right)$
   4. D.$2\left({\mathrm{P}}_1{\mathrm{V}}_1-{\mathrm{P}}_2{\mathrm{V}}_2\right)$
   Show answer

   Answer: D

7. Q362024 · 31 Jan 2024 · Shift 1

   An artillery piece of mass $M_1$ fires a shell of mass $M_2$ horizontally. Instantaneously after the firing, the ratio of kinetic energy of the artillery and that of the shell is:

   1. A.$M_1/(M_1+M_2)$
   2. B.$\frac{M_2}{M_1}$
   3. C.$\frac{M_1}{M_2}$
   4. D.$M_2/(M_1+M_2)$
   Show answer

   Answer: B

8. Q312024 · 30 Jan 2024 · Shift 1

   The ratio of the magnitude of the kinetic energy to the potential energy of an electron in the $5^{\text{th}}$ excited state of a hydrogen atom is :

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

   Answer: C

9. Q492024 · 29 Jan 2024 · Shift 1

   The potential energy function (in $J$ ) of a particle in a region of space is given as $U=(2x^2+3y^3+2z)$. Here $x,y$ and $z$ are in meter. The magnitude of $x$-component of force (in $N$ ) acting on the particle at point $P(1,2,3)\text{m}$ is :

   1. A.$4$
   2. B.$2$
   3. C.$8$
   4. D.$6$
   Show answer

   Answer: A

10. Q472024 · 27 Jan 2024 · Shift 2

    The total kinetic energy of 1 mole of oxygen at $27^{\circ }\text{C}$ is : [Use universal gas constant $(R)=8.31\text{ J/mole K}$]

    1. A.$6232.5\text{ J}$
    2. B.$5670.5\text{ J}$
    3. C.$6845.5\text{ J}$
    4. D.$5942.0\text{ J}$
    Show answer

    Answer: A