1
JEE Main 2026 (Online) 23rd January Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

A cup of water at $5^{\circ} \mathrm{C}$ (system) is placed in a microwave oven and the oven is turned on for one minute during which the water begins to boil. Which of the following option is true?

A

$q=+v e, w=-v e, \Delta U=+v e$

B

$q=+v e, w=0, \Delta U=-v e$

C

$q=+v e, w=-v e, \Delta U=-v e$

D

$q=-v e, w=-v e, \Delta U=-v e$

2
JEE Main 2026 (Online) 22nd January Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

$$ \text { Match the LIST-I with LIST-II } $$

List-I Thermodynamic Process List-II Magnitude in kJ
A. Work done in reversible, isothermal expansion of 2 mol of ideal gas from 2
<mrow data-mjx-texclass="ORD">

  <mi data-mjx-auto-op="false">dm</mi>

</mrow>

<mn>3</mn>
2
<mrow data-mjx-texclass="ORD">

  <mi data-mjx-auto-op="false">dm</mi>

</mrow>

<mn>3</mn>
2dm^(3)
to 20
<mrow data-mjx-texclass="ORD">

  <mi data-mjx-auto-op="false">dm</mi>

</mrow>

<mn>3</mn>
20
<mrow data-mjx-texclass="ORD">

  <mi data-mjx-auto-op="false">dm</mi>

</mrow>

<mn>3</mn>
20dm^(3)
at 300 K .
I. 4
B. Work done in irreversible isothermal expansion of 1 mol ideal gas from 1
<mrow data-mjx-texclass="ORD">

  <mtext> </mtext>

  <mi mathvariant="normal">m</mi>

</mrow>

<mn>3</mn>
1
<mrow data-mjx-texclass="ORD">

  <mtext></mtext>

  <mi mathvariant="normal">m</mi>

</mrow>

<mn>3</mn>
1m^(3)
to 3
<mrow data-mjx-texclass="ORD">

  <mtext> </mtext>

  <mi mathvariant="normal">m</mi>

</mrow>

<mn>3</mn>
3
<mrow data-mjx-texclass="ORD">

  <mtext></mtext>

  <mi mathvariant="normal">m</mi>

</mrow>

<mn>3</mn>
3m^(3)
at 300 K against a constant pressure of 3 kPa .
II. 11.5
C. Change in internal energy for adiabatic expansion of a 1 mol ideal gas with change of temperature = 320
<mtext> </mtext>

<mi mathvariant="normal">K</mi>
= 320
<mtext></mtext>

<mi mathvariant="normal">K</mi>
=320K
and
<mover>

  <mrow data-mjx-texclass="ORD">

    <mi mathvariant="normal">C</mi>

  </mrow>

  <mo accent="true">―</mo>

</mover>

<mrow data-mjx-texclass="ORD">

  <mrow data-mjx-texclass="ORD">

    <mi mathvariant="normal">V</mi>

  </mrow>

</mrow>
=
<mn>3</mn>

<mn>2</mn>
<mi mathvariant="normal">R</mi>
<mover accentunder="false">

  <mrow data-mjx-texclass="ORD">

    <mi mathvariant="normal">C</mi>

  </mrow>

  <mo>¯</mo>

</mover>

<mrow data-mjx-texclass="ORD">

  <mrow data-mjx-texclass="ORD">

    <mi mathvariant="normal">V</mi>

  </mrow>

</mrow>
=
<mn>3</mn>

<mn>2</mn>
<mi mathvariant="normal">R</mi>
bar(C)_(V)=(3)/(2)R
.
III. 6
D. Change in enthalpy at constant pressure of 1 mol ideal gas with change of temperature = 337
<mtext> </mtext>

<mi mathvariant="normal">K</mi>
= 337
<mtext></mtext>

<mi mathvariant="normal">K</mi>
=337K
and
<mover>

  <mrow data-mjx-texclass="ORD">

    <mi mathvariant="normal">C</mi>

  </mrow>

  <mo accent="true">―</mo>

</mover>

<mrow data-mjx-texclass="ORD">

  <mrow data-mjx-texclass="ORD">

    <mi mathvariant="normal">p</mi>

  </mrow>

</mrow>
=
<mn>5</mn>

<mn>2</mn>
<mi mathvariant="normal">R</mi>
<mover accentunder="false">

  <mrow data-mjx-texclass="ORD">

    <mi mathvariant="normal">C</mi>

  </mrow>

  <mo>¯</mo>

</mover>

<mrow data-mjx-texclass="ORD">

  <mrow data-mjx-texclass="ORD">

    <mi mathvariant="normal">p</mi>

  </mrow>

</mrow>
=
<mn>5</mn>

<mn>2</mn>
<mi mathvariant="normal">R</mi>
bar(C)_(p)=(5)/(2)R
.
IV. 7
A

A-I, B-II, C-III, D-IV

B

A-III, B-II, C-IV, D-I

C

A-II, B-I, C-III, D-IV

D

A-II, B-III, C-I, D-IV

3
JEE Main 2026 (Online) 21st January Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

Consider the following data :

$\Delta_{f}H^{\circ}$ (methane, g) = $-X \; \text{kJ mol}^{-1}$

Enthalpy of sublimation of graphite = $Y \; \text{kJ mol}^{-1}$

Dissociation enthalpy of $H_2 = Z \; \text{kJ mol}^{-1}$

The bond enthalpy of C–H bond is given by :

A

$ \dfrac{X + Y + 2Z}{4} $

B

$ \dfrac{X + Y + 4Z}{2} $

C

$ \dfrac{-X + Y + Z}{4} $

D

$X + Y + Z$

4
JEE Main 2026 (Online) 21st January Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

Which of the following graphs between pressure ' p ' versus volume ' V ' represents the maximum work done?

A
JEE Main 2026 (Online) 21st January Morning Shift Chemistry - Thermodynamics Question 16 English Option 1
B
JEE Main 2026 (Online) 21st January Morning Shift Chemistry - Thermodynamics Question 16 English Option 2
C
JEE Main 2026 (Online) 21st January Morning Shift Chemistry - Thermodynamics Question 16 English Option 3
D
JEE Main 2026 (Online) 21st January Morning Shift Chemistry - Thermodynamics Question 16 English Option 4

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