MCQOPTIONS
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MCQOPTIONS
This section includes 28 Mcqs, each offering curated multiple-choice questions to sharpen your Physics knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
For an adiabatic expansion of a perfect gas, the value of \[\frac{\Delta P}{P}\] is equal to [CPMT 1983; MP PMT 1990] |
| A. | \[-\sqrt{\gamma }\frac{\Delta V}{V}\] |
| B. | \[-\frac{\Delta V}{V}\] |
| C. | 30°C |
| D. | \[-{{\gamma }^{2}}\frac{\Delta V}{V}\] |
| Answer» D. \[-{{\gamma }^{2}}\frac{\Delta V}{V}\] | |
| 2. |
A gas for which \[\gamma =1.5\]is suddenly compressed to\[\frac{1}{4}\]th of the initial volume. Then the ratio of the final to the initial pressure is [EAMCET 2001] |
| A. | 1 : 16 |
| B. | 1 : 8 |
| C. | Entropy |
| D. | 8 : 1 |
| Answer» E. | |
| 3. |
A polyatomic gas \[\left( \gamma =\frac{4}{3} \right)\] is compressed to \[\frac{1}{8}\] of its volume adiabatically. If its initial pressure is \[{{P}_{o}}\], its new pressure will be [MP PET 1994; BHU 1995] |
| A. | \[8{{P}_{o}}\] |
| B. | \[16{{P}_{0}}\] |
| C. | AB, BC, CD |
| D. | \[2{{P}_{o}}\] |
| Answer» C. AB, BC, CD | |
| 4. |
In pressure-volume diagram given below, the isochoric, isothermal, and isobaric parts respectively, are [Manipal MEE 1995] |
| A. | BA, AD, DC |
| B. | DC, CB, BA |
| C. | 8 times |
| D. | CD, DA, AB |
| Answer» E. | |
| 5. |
A system goes from A to B via two processes I and II as shown in figure. If \[\Delta {{U}_{1}}\] and \[\Delta {{U}_{2}}\] are the changes in internal energies in the processes I and II respectively, then [AIEEE 2005] |
| A. | \[\Delta {{U}_{\text{II}}}>\Delta {{U}_{\text{I}}}\] |
| B. | \[\Delta {{U}_{\text{II}}}<\Delta {{U}_{\text{I}}}\] |
| C. | 1.5 s |
| D. | Relation between \[\Delta {{U}_{\text{I}}}\] and \[\Delta {{U}_{\text{II}}}\] can not be determined |
| Answer» D. Relation between \[\Delta {{U}_{\text{I}}}\] and \[\Delta {{U}_{\text{II}}}\] can not be determined | |
| 6. |
Temperature is a measurement of coldness or hotness of an object. This definition is based on [RPET 2003] |
| A. | Zeroth law of thermodynamics |
| B. | First law of thermodynamics |
| C. | \[{{10}^{o}}C\] |
| D. | Newton's law of cooling |
| Answer» B. First law of thermodynamics | |
| 7. |
One mole of an ideal monoatomic gas is heated at a constant pressure of one atmosphere from \[{{0}^{o}}C\] to \[{{100}^{o}}C\]. Then the change in the internal energy is [Pb. PMT 2001] |
| A. | 6.56 joules |
| B. | \[8.32\times {{10}^{2}}\]joules |
| C. | Thermal conductivity |
| D. | 20.80 joules |
| Answer» D. 20.80 joules | |
| 8. |
A system is provided with 200 cal of heat and the work done by the system on the surrounding is 40 J. Then its internal energy [Orissa PMT 2004] |
| A. | Increases by 600 J |
| B. | Decreases by 800 J |
| C. | 1 : 9 |
| D. | Decreases by 50 J |
| Answer» D. Decreases by 50 J | |
| 9. |
For free expansion of the gas which of the following is true [AMU (Med.) 2000] |
| A. | \[Q=W=0\] and \[\Delta \,{{E}_{\operatorname{int}}}=0\] |
| B. | \[Q=0,\,W>0\] and \[\Delta {{E}_{\operatorname{int}}}=-W\] |
| C. | If assertion is true but reason is false. |
| D. | \[W>0,\,Q<0\] and \[\Delta {{E}_{\operatorname{int}}}=0\] |
| Answer» B. \[Q=0,\,W>0\] and \[\Delta {{E}_{\operatorname{int}}}=-W\] | |
| 10. |
Which of the following is not thermodynamical function [CBSE PMT 1993; CPMT 2001; DCE 1996; 2001] |
| A. | Enthalpy |
| B. | Work done |
| C. | If assertion is true but reason is false. |
| D. | Internal energy |
| Answer» C. If assertion is true but reason is false. | |
| 11. |
First law of thermnodynamics is given by [CPMT 1977, 91] |
| A. | \[dQ=dU+PdV\] |
| B. | \[dQ=dU\times PdV\] |
| C. | If assertion is true but reason is false. |
| D. | \[dQ=PdU+dV\] |
| Answer» B. \[dQ=dU\times PdV\] | |
| 12. |
Following reaction occurring in an automobile \[2{{C}_{8}}{{H}_{18}}(g)+25{{O}_{2}}(g)\to 16C{{O}_{2}}(g)+18{{H}_{2}}O(g).\] The sign of \[\Delta H,\,\Delta S\] and \[\Delta G\] would be [CBSE PMT 1994; KCET 1999] |
| A. | +, ?, + |
| B. | ?, +, ? |
| C. | If assertion is true but reason is false. |
| D. | +, +, ? |
| Answer» C. If assertion is true but reason is false. | |
| 13. |
When \[50c{{m}^{3}}\] of \[0.2\,N\,{{H}_{2}}S{{O}_{4}}\] is mixed with \[50c{{m}^{3}}\] of \[1\,N\,KOH\], the heat liberated is [KCET 2004] |
| A. | 11.46 kJ |
| B. | 57.3 kJ |
| C. | \[1\,cm\] |
| D. | 573 J |
| Answer» E. | |
| 14. |
The \[{{H}_{2}}O(g)\] molecule dissociates as (i) \[{{H}_{2}}O(g)\to H(g)+OH(g);\,\Delta H=490\,kJ\] (ii) \[OH(g)\to H(g)+O(g);\,\Delta H=424\,kJ\] The average bond energy (in kJ) for water is |
| A. | 490 |
| B. | 424 |
| C. | \[{{\alpha }_{1}}=3{{\alpha }_{2}}\] |
| D. | 914/2 |
| Answer» E. | |
| 15. |
When a gas undergoes adiabatic expansion, it gets cooled due to [DCE 2002] |
| A. | Loos of kinetic energy |
| B. | Fall in temperature |
| C. | 7.4 cm |
| D. | Energy used in doing work |
| Answer» C. 7.4 cm | |
| 16. |
The value of heat generated when 36.5 gm \[HCl\] and 40 gm of \[NaOH\] reacts during neutralization [NCERT 1984; CPMT 1993] |
| A. | 76.5 kcal |
| B. | 13.7 kcal |
| C. | 0.153 cc |
| D. | 108 kcal |
| Answer» C. 0.153 cc | |
| 17. |
Heat of neutralization of strong acid against strong base is constant and is equal to [EAMCET 1980; AFMC 1989; DPMT 1991; MP PET 1999; BHU 1999; MP PMT 1995] |
| A. | 13.7 kcal |
| B. | 57 kJ |
| C. | Triple point |
| D. | All of the above |
| Answer» E. | |
| 18. |
Following figure shows on adiabatic cylindrical container of volume \[{{V}_{0}}\] divided by an adiabatic smooth piston (area of cross-section = A) in two equal parts. An ideal gas \[({{C}_{P}}/{{C}_{V}}=\gamma )\] is at pressure P1 and temperature T1 in left part and gas at pressure P2 and temperature T2 in right part. The piston is slowly displaced and released at a position where it can stay in equilibrium. The final pressure of the two parts will be (Suppose x = displacement of the piston) |
| A. | \[{{P}_{2}}\] |
| B. | \[{{P}_{1}}\] |
| C. | 80 gm |
| D. | \[\frac{{{P}_{2}}{{\left( \frac{{{V}_{0}}}{2} \right)}^{\gamma }}}{{{\left( \frac{{{V}_{0}}}{2}+Ax \right)}^{\gamma }}}\] |
| Answer» D. \[\frac{{{P}_{2}}{{\left( \frac{{{V}_{0}}}{2} \right)}^{\gamma }}}{{{\left( \frac{{{V}_{0}}}{2}+Ax \right)}^{\gamma }}}\] | |
| 19. |
Two samples A and B of a gas initially at the same pressure and temperature are compressed from volume V to V/2 (A isothermally and adiabatically). The final pressure of A is [MP PET 1996, 99; MP PMT 1997, 99] |
| A. | Greater than the final pressure of B |
| B. | Equal to the final pressure of B |
| C. | \[\frac{t}{2}\] |
| D. | Twice the final pressure of B |
| Answer» D. Twice the final pressure of B | |
| 20. |
Which of the following would be expected to have the largest antropy per mole [MP PMT 2004] |
| A. | \[S{{O}_{2}}C{{l}_{2}}(s)\] |
| B. | \[S{{O}_{2}}C{{l}_{2}}(g)\] |
| C. | ? 5°C |
| D. | \[S{{O}_{2}}(g)\] |
| Answer» E. | |
| 21. |
In endothermic reaction, the value of change in enthalpy \[(\Delta H)\] is [Pb. CET 2001] |
| A. | Positive |
| B. | Negative |
| C. | 40°C |
| D. | None of these |
| Answer» B. Negative | |
| 22. |
Two Carnot engines A and B are operated in succession. The first one, A receives heat from a source at \[{{T}_{1}}=800k\] and rejects to sink at \[{{T}_{2}}k.\]. The second engine B receives heat rejected by the first engine and rejects to another sink at \[{{T}_{3}}=300k.\] If the work outputs of two engines are equal, then the value of \[{{T}_{2}}\] is |
| A. | 100K |
| B. | 300K |
| C. | 150°C |
| D. | 700K |
| Answer» D. 700K | |
| 23. |
Assertion : The internal energy of an isothermal process does not change. Reason : The internal energy of a system depends only on pressure of the system. |
| A. | If both assertion and reason are true and the reason is the correct explanation of the assertion. |
| B. | If both assertion and reason are true but reason is not the correct explanation of the assertion. |
| C. | Equal |
| D. | If the assertion and reason both are false. |
| E. | If assertion is false but reason is true. |
| Answer» D. If the assertion and reason both are false. | |
| 24. |
Assertion : Work and heat are two equivalent form of energy. Reason : Work is the transfer of mechanical energy irrespective of temperature difference, whereas heat is the transfer of thermal energy because of temperature difference only. |
| A. | If both assertion and reason are true and the reason is the correct explanation of the assertion. |
| B. | If both assertion and reason are true but reason is not the correct explanation of the assertion. |
| C. | 60 cal |
| D. | If the assertion and reason both are false. |
| E. | If assertion is false but reason is true. |
| Answer» B. If both assertion and reason are true but reason is not the correct explanation of the assertion. | |
| 25. |
During an adiabatic process, the pressure of a gas is found to be proportional to the cube of its absolute temperature. The ratio \[{{C}_{p}}/{{C}_{v}}\] for the gas is [AIEEE 2003] |
| A. | \[\frac{3}{2}\] |
| B. | \[\frac{4}{3}\] |
| C. | Equally dangerous |
| D. | \[\frac{5}{3}\] |
| Answer» B. \[\frac{4}{3}\] | |
| 26. |
The process in which no heat enters or leaves the system is termed as [Pb. PET 1996; BHU 1998; BCECE 2003] |
| A. | Isochoric |
| B. | Isobaric |
| C. | 1600 gm |
| D. | Adiabatic |
| Answer» E. | |
| 27. |
One mole of helium is adiabatically expanded from its initial state \[({{P}_{i}},{{V}_{i}},{{T}_{i}})\] to its final state \[({{P}_{f}},{{V}_{f}},{{T}_{f}})\]. The decrease in the internal energy associated with this expansion is equal to [SCRA 1994; BHU 2002] |
| A. | \[{{C}_{V}}({{T}_{i}}-{{T}_{f}})\] |
| B. | \[{{C}_{P}}({{T}_{i}}-{{T}_{f}})\] |
| C. | If assertion is true but reason is false. |
| D. | \[({{C}_{P}}-{{C}_{V}})({{T}_{i}}-{{T}_{f}})\] |
| Answer» B. \[{{C}_{P}}({{T}_{i}}-{{T}_{f}})\] | |
| 28. |
Which is the correct statement [MP PMT 1993] |
| A. | For an isothermal change PV = constant |
| B. | In an isothermal process the change in internal energy must be equal to the work done |
| C. | \[\Delta {{U}_{\text{I}}}=\Delta {{U}_{\text{II}}}\] |
| D. | In an adiabatic process work done must be equal to the heat entering the system |
| Answer» B. In an isothermal process the change in internal energy must be equal to the work done | |