First Law of Thermodynamics PYQs: JEE Mains Physics

Showing 1–14 of 14 questions

1. 1. Consider the following statements:
   A. Zeroth law of thermodynamics gives concept of temperature
   B. First law of thermodynamics gives concept of internal energy
   C. In isothermal expansion of ideal gas, \(\Delta Q \neq \Delta W\)
   D. Product of intensive and extensive variables is extensive
   E. The ratio of any extensive variable to mass will be an extensive variable
   Choose the correct combination of statements from the options given below: 2026 Medium
2. 2. Heat is supplied to a diatomic gas at constant pressure. Then the ratio of \(\Delta Q : \Delta U : \Delta W\) is _______. 2026 Medium
3. 3. One mole of diatomic gas having rotational modes only is kept in a cylinder with a piston system. The cross-section area of the cylinder is \(4\) cm\(^2\). The gas is heated slowly to raise the temperature by \(1.2\,^\circ\)C during which the piston moves by \(25\) mm. The amount of heat supplied to the gas is ________ J. (Atmospheric pressure \(=100\) kPa, \(R=8.3\) J/mol·K) (Neglect mass of the piston) 2026 Hard
4. 4. The internal energy of a monoatomic gas is 3 nRT . One mole of helium is kept in a cylinder having internal cross section area of \(17 cm^2\) and fitted with a light movable frictionless piston. The gas is heated slowly by suppling 126 J heat. If the temperature rises by \(4^{\circ} C\), then the piston will move ___________ cm.
   (atmospheric pressure \(=10^5 Pa\) ) 2026 Medium
5. 5. During the melting of a slab of ice at 273 K at atmospheric pressure : 2025 Easy
6. 6. Given are statements for certain thermodynamic variables,
   (A) Internal energy, volume (V) and mass (M) are extensive variables.
   (B) Pressure (P), temperature (T) and density ( \(\rho\) ) are intensive variables.
   (C) Volume (V), temperature (T) and density ( \(\rho\) ) are intensive variables.
   (D) Mass (M), temperature (T) and internal energy are extensive variables.
   
   Choose the correct answer from the options given below : 2025 Easy
7. 7. 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, \(\mathrm{R}=8.3 \mathrm{~J} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}\).) 2024 Hard
8. 8. \(1\,g\) of a liquid is converted to vapour at \(3 \times 10^5\,Pa\) pressure. If \(10 \%\) of the heat supplied is used for increasing the volume by \(1600\,cm ^3\) during this phase change, then the increase in internal energy in the process will be \(............\,J\) 2023 Medium
9. 9. A gas is compressed adiabatically, which one of the following statement is NOT true. 2023 Medium
10. 10. A source supplies heat to a system at the rate of \(1000 \,W\). If the system performs work at a rate of \(200\,W\). The rate at which internal energy of the system increases \(.......\,W\) 2023 Easy
11. 11. Given below are two statements. One is labelled as Assertion A and the other is labelled as Reason \(R\). Assertion \(A\) : If \(dQ\) and \(dW\) represent the heat supplied to the system and the work done on the system respectively. Then according to the first law of thermodynamics \(d Q=d U-d W\). Reason \(R :\) First law of thermodynamics is based on law of conservation of energy. In the light of the above statements, choose the correct answer from the option given below : 2023 Medium
12. 12. Given below are two statements: Statement \(I:\) If heat is added to a system, its temperature must increase. Statement \(II:\) If positive work is done by a system in a thermodynamic process, its volume must increase. In the light of the above statements, choose the correct answer from the options given below 2023 Medium
13. 13. An electric appliance supplies \(6000\, {J} / {min}\) heat to the system. If the system delivers a power of \(90\, {W}\). How long (in \(sec\)) it would take to increase the internal energy by \(2.5 \times 10^{3}\, {J}\) ? 2021 Medium
14. 14. The amount of heat needed to raise the temperature of \(4\, moles\) of a rigid diatomic gas from \(0^{\circ} {C}\) to \(50^{\circ} {C}\) when no work is done is ......\({R}\) (\(R\) is the universal gas constant) 2021 Medium

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