Q.1
If a wire of resistance 20Ω is covered with ice and voltage of 210V is applied across the wire then rate of melting of ice will be ..[ AFMC 1997]
  • a) 6.56 g/s
  • b) 0.85 g/s
  • c)3.56 g/s
  • d)none of these
Q.2
The ratio of speed of sound in Helium and Hydrogen gases at the same temperature is ..[ AFMC 1998]
  • a) √42:√25
  • b) √25:√42
  • c)42:45
  • d)25:42
Q.3
When the amount of work done is 300 J and change in internal energy is 100J, then the heat supplied is..[ AFMC 1998]
  • a) 400 J
  • b) 350 J
  • c) 200 J
  • d) 150 J
Q.4
Water falls from a height 500m. The rise in temperature of water at bottom if whole of the energy remains in water, will be ( specific heat of water is 4.2 kJ/kg) [AFMC 1997]
  • a)0.23°C
  • b) 1.16°C
  • c)096°C
  • d)1.02°C
Q.5
16g of oxygen at 37°C is mixed with 14 g of nitrogen at 27°C, the temperature of the mixture will be...[ AFMC 1997]
  • a) 30.5°C
  • b) 37°C
  • c)27°C
  • d)32°C
Q.6
When there is no heat exchange from surrounding to a system, then the process is related with. [ AFMC 1997]
  • a) isobaric
  • b) isochoric
  • c)isothermal
  • d)adiabatic
Q.7
If the ratio of specific heat of gas at constant pressure to that at constant volume is γ, the change in internal energy of one mole of gas when the volume changes from V to 2V at constant pressure P is ...[ AFMC 1997]
  • a) γPV/(γ -1)
  • b) PV/(γ -1)
  • c) R/(γ -1)
  • d) PV
Q.8
The original temperature of a black body is 727°C. The temperature to which that black body must be raised so as to double the total radiant energy, is .. [ AFMC 1997]
  • a)917°C
  • b) 1190°C
  • c)1454°C
  • d)2000K
Q.9
If the heat of 110J is added to a gaseous system, whose internal energy is 40J, then the amount of external work done is ...[ AFMC 1999]
  • a)80 J
  • b) 70 J
  • c)114 J
  • d)140 J
Q.10
If the coefficient of cubical expansion is 'x' times of the coefficient of superficial expansion, then value of 'x' is [ AFMC 2000]
  • a) 1/2
  • b) 1
  • c)1.5
  • d)4
Q.11
A body radiates 5W energy at a temperature of 400K. If the temperature is increased to 1200K then it radiates energy at the rate of ...[ AFMC 2000]
  • a) 419 W
  • b) 405 W
  • c)210 W
  • d)80 W
Q.12
The maximum energy in the thermal radiation from a heat source occurs at a wave length of 11×10-5cm. according to wein's displacement Law the temperature of this source will be 'n' times. The temperature of another source for which the wavelength at maximum energy is 5.5×10-5cm. Then the value of n is [ AFMC 2000]
  • a) 1/2
  • b) 1
  • c) 2
  • d) 4
Q.13
A ideal gas A and real gas B have their volumes increased from V to 2V under isothermal conditions. The increase in internal energy. [ CBSE-PMT 1993]
  • a)will be same in both A and B
  • b) will be zero in both the gas
  • c)of B will be more than that of A
  • d)of A will be more than that of B
Q.14
The temperature of source and sink of a heat engine are 127° and 27°C respectively. An inventor claims its efficiency to be 26%, then...[ CBSE-PMT 2001]
  • a) it is impossible
  • b) it is possible with high probability
  • c)it is possible with low probability
  • d)data are insufficient
Q.15
A diatomic gas initially at 18°C is compressed adiabatically to one eight of its original volume. The temperature after compression will be ... [ CBSE-PMT 1996]
  • a) 18°C
  • b) 668.4°K
  • c)395.4°C
  • d)144°C
Q.16
A mass of diatomic gas (γ=1.4) at a pressure of 2atmosphere is compressed adiabatically so that its temperature rises from 27°C to 927°C. The pressure of the gas is final state is .. [ CBSE-PMT 2011]
  • a) 28 atm
  • b) 68.7 atm
  • c) 256 atm
  • d) 8 atm
Q.17
When 1kg of ice at 0°C metals to water at 0°C, the resulting change in its entropy, taking latent heat of ice to be 80cal/°C, is .. [ CBSE-PMT 2011]
  • a)273 cal/K
  • b) 8×104 cal/K
  • c)80 cal/K
  • d)293 cal/K
Q.18
Which of the following is not thermo dynamical function? [ CBSE-PMT 1993]
  • a) Enthalpy
  • b) Work done
  • c)Gibbs's energy
  • d)Internal energy
Q.19
The internal energy change in a system that has absorbed 2 kcal of heat and done 500J of work is [ CBSE-PMT 2009]
  • a) 6400 J
  • b) 5400 J
  • c)7900 J
  • d)8900 J
Q.20
A sample of gas expands from volume V1 to VThe amount of work done by the gas is greatest hen the expansion is ... [ CBSE-PMT 1997]
  • a) adiabatic
  • b) isobaric
  • c) isothermal
  • d) equal in all cases
Q.21
A Carnot engine whose sink is at 300K has an efficiency of 40%. By how much should the temperature of source be increased so as to increase its efficiency by 50% of original efficiency? [ CBSE-PMT 2006]
  • a)325K
  • b) 250K
  • c) 380K
  • d)275K
Q.22
Which of the following process is reversible? [ CBSE-PMT 2005]
  • a) Transfer of heat by conduction
  • b) Transfer of heat by radiation
  • c)Isothermal compression
  • d)Electrical heating of a nichrome wire
Q.23
We consider a thermodynamic system. If represents the increase in its internal energy of W the work done by the system, which of the following statement is true? [ CBSE-PMT 1998]
  • a) ΔU=-W in an adiabatic process
  • b) ΔU=W in an isothermal process
  • c)Δ U=-W in an isothermal process
  • d)ΔU=W in an adiabatic process
Q.24
An engine has efficiency of 1/When the temperature of sink is reduced by 62°C, its efficiency is doubled. Temperature of the source is [ CBSE-PMT 2007]
  • a) 37°
  • b) 62°
  • c) 99°
  • d) 124°
Q.25
An ideal carnot engine, whose efficiency is 40% receives heat at 500K. If its efficiency is 50% then intake temperature for the same exhaust temperature is [ CBSE-PMT 1995]
  • a)600 K
  • b) 700 K
  • c)800 K
  • d)900 K
Q.26
110 joules of heat is added to a gaseous system. Whose internal energy is 40J, then the amount of external work done is .. [ CBSE-PMT 1993]
  • a) 150J
  • b) 70J
  • c)110J
  • d)40 J
Q.27
If Q, E and W denote respectively the heat added change in internal energy and the work done in a closed cyclic process then [ CBSE-PMT 2008]
  • a) W=0
  • b) Q=W=0
  • c)E=0
  • d)Q=0
Q.28
If the ratio of specific heat of a gas constant pressure to that at constant volume is γ, the change in internal energy of mass of gas, when the volume changes from V and 2V at constant pressure P, is ... [ CBSE-PMT 1998]
  • a)
    ch-12_qn-28choice_img_no1.png
  • b) PV
    ch-12_qn-28choice_img_no3.png
  • c)
    ch-12_qn-28choice_img_no4.png
  • d)
Q.29
The volume of gas reduced adiabatically to 1/4 of its volume at 27°C. If γ=1.4 the new temperature is ..[ MPPMT 1990]
  • a) (300)(2)0.4 K
  • b) (300)(4)1.4 K
  • c)(300)(4)0.4 K
  • d)(300)(2)1.4 K
Q.30
A reversible engine converts one-sixth of the heat input into work. When the temperature of the sink is reduced by 62°C, the efficiency of the engine is doubled. The temperatures of the source and sink are... [ CBSE-PMT 2000]
  • a)99°C, 37°C
  • b) 80°C, 37°C
  • c)95°C, 37°C
  • d)90°C, 37°C
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