UNIT#05 THERMODYNAMICS Flashcards
(319 cards)
1
Q
The heat was given to a body, which raises its temperature by 1°C is _____.
A
Specific Heat
2
Q
The thermal capacity of 40g of aluminium (specific heat 0.2 cal0g-1C-1) is _____.
A
8 cal0C-1
(Thermal capacity=mc)
3
Q
80g of water at 30°C is poured on a large block of ice which is at 0°C. The mass of ice
A
30 g
4
Q
Mud houses are cooler in summer and warmer in winter because;
A
Mud is a bad conductor of heat
5
Q
The heat capacity of a substance is infinite. It means ____
A
No change in temprature
6
Q
The change in internal energy, when a gas is cooled from 927°C to 27°C is?
A
75%
(U=mcΔT)
7
Q
Two cylinders of equal size are filled with an equal amount of ideal diatomic gas at room temperature. Both the cylinders are fitted with pistons. In-cylinder A the piston is free to move, while in cylinder B the piston is fixed. When the same amount of heat is added to cylinder A raises by 20K. What will be the rise in the temperature of the gas in cylinder B?
A
28K
8
Q
The relation for the 1st law of thermodynamics can be expressed as:
A
ΔQ = ΔU + ΔW
9
Q
Examples of the first law of thermodynamics are;
A
➡Working on a bicycle pump
➡Brakes applied by an automobile
➡Human Metabolism
10
Q
1st law of thermodynamics is a consequence of the conservation of:
A
Energy
11
Q
Which statement about the first law of thermodynamics is correct?
A
The increase in the internal energy of a system equals the heating of the system minus the work done by the system
12
Q
In a thermodynamic system working substance is an ideal gas, its internal energy is in the form of;
A
Kinetic Energy only
➡Adiabatic Process
(Ideal gas possesses only K.E)
13
Q
In an ideal gas, the molecules possess?
A
Ony K.E
14
Q
Which one is true for internal energy?
A
➡It is the sum of all forms of molecular energies of the system
➡It is proportional to translational K.E of the molecules
➡It is a state function of a system
15
Q
If two systems X and Y are in thermal equilibrium. If X is heated at constant volume and Y is heated at constant pressure, and again finally maintained at thermal equilibrium, then heat given to the systems X and Y and internal energy U stored in the systems X and Y are;
A
➡Qx < Qy
➡Ux = Uy
16
Q
The internal energy of a body is maximum when its temperature is;
A
273K
(Internal Energy ∝ Translational K.E ∝ Temperature
17
Q
An ideal gas is pressed at a constant temperature,. Its internal energy
A
Remains the same
18
Q
When 20J of work was done on the gas, 40J of heat energy was released. If the initial internal energy of the gas was 70J, what is the final internal energy?
A
50J
(Q = ΔU - W)
19
Q
By rubbing the objects together, their internal energy;
A
Increases
20
Q
The internal energy of an ideal gas depends upon only;
A
Temperature
21
Q
If a system undergoes contraction of volume, then the work done by the system will be:
A
Negative
22
Q
The work done in the isochoric process is;
A
Zero
(W=PΔV)
➡As volume is constant, so ΔV=0
23
Q
Q
Work done by air when it expands from 50 litres to 150 litres at a constant pressure of 2 atm is;
A
2 x 10^4 J
24
Q
The equation W = P(V2 -1 V1) represents work done by the gas in;
A
an expansion at constant pressure
25
Find the change in internal energy of the system when a system absorbs 2 kilocalories o heat and at the same time does 500 joules of work;
7900 J
(Q = W + ΔU)
26
A system is described in terms of thermodynamics variable;
➡Pressure
➡Temperature
➡Volume
27
The concept of temperature is related to;
Zeroth Law of thermodynamics
28
Which of the following statement is correct or any thermodynamic system?
➡The internal energy changes in all processes❌
➡The change in entropy can never be zero❌
➡Internal energy and entropy are state functions ✅
➡The work done in an adiabatic process is always zero❌
29
Thermodynamics is the study of the relationship between;
Heat & other forms of energy
30
Heat added at a constant volume of a gas is used to:
To increase its internal energy
31
When heat is given to gas is an isobaric process then;
➡The work is done by the gas
➡Internal Energy of the gas increases
32
If the volume of a gas is decreased by 10% during the isothermal process then its pressure will:
Increase by 11.11%
33
During this process the volume of the system remains constant:
Isochoric
34
A gas does 10J of external work in an adiabatic process while expanding, then the change in internal energy is;
-10 J
(Q = ΔU + W)
35
During the adiabatic expansion of 2 moles of a gas, the internal energy of the gas is found to decrease by 2 joules, the work done during the process on the gas will be equal to;
2J
(Q = ΔU + W)
36
Starting with the same initial conditions, an ideal gas expands from volume V1 to V2 in three different ways. The work done by the gas is W1 if the process is purely isothermal. W2 if purely isobaric and W3 if purely adiabatic then;
W2>W1>W3
37
Cp - Cv value, find if 3 moels of gas give:
3R
38
A valid unit of specific heat capacity is;
Jkg-1K-1
39
If 1 mole of monoatomic gas γ=5/3 is mixed with 1 mole of diatomic gas γ=7/5. What is the value of γ for the mxiture?
1.5
40
Find the internal energy of the system containing 2 moles of oxygen and 4 moles of argon:
11RT
41
If the energy required to raise the temperature of 10°C is 20J at constant volume then how much energy is required to raise the same temperature at constant pressure?
40 J
42
Find the molar-specific heat capacity of diatomic gas which work done is Q/4 if heat is given to the system>
10/3 R
43
The internal energy of one gram of helium at 100K and one atmospheric pressure is;
300J
44
310 J of heat is required to raise the temperature of 2 moels of an ideal gas at constant pressure from 25°C to 35°C. The amount of heat energy required to raise the temperature of gas through the same range at constant volume is:
143J
45
The first law of thermodynamics is related to:
Law of conservation of energy
46
Cv/ Cp is equal to:
1/γ
47
When Cp = 20 J/kg k and 1 mole of gas is present then Cv is?
4.36 J/kgk
48
1 gamma for poly atomic gas is;
1.29
49
Which one is true about Cv and Cp?
Cp > Cv
50
Which of the following is incorrect?
➡Cp - Cv = R❌
➡Cp = R - Cv❌
➡Cp/Cv = R✅
➡ R + Cp = Cv❌
51
If the pressure of diatomic gas varies as P = aV2 then its heat capacity will:
17 R/6
52
Specific heat capacity in terms of heat capacity is;
C/m
53
At 0° K which of the following properties of gas will be zero
Kinetic Energy
54
What will be changed in internal energy when work is done by the system is 50KJ heat absorbed is 40 KJ
-10KJ
55
Gas laws are applicable to:
Gases alone and not to vapours
56
An ideal gas as compared to a real gas at very high pressure occupies:
More volume
57
The unit of pressure in the S.I Unit is
Pascal
58
Thermodynamics does not consider:
Time Factor
59
A system which can neither exchange matter nor energy with the surroundings is called:
Isolated system
60
Absolute zero temperature is taken as;
-273°C
61
In the isothermal process:
Temperature is constant
62
Absolute zero pressure will be;
When molecule moment o system is zero
63
If the volume of a gas is held constant and we increase its temperature then:
Its pressure rises
64
For a gas obeying Boyles's law, if the pressure is doubled the volume becomes:
One half
65
If Cp = 34.4 J/mol K and the value of R is 8.314 then:
Cv = 26.1 J/mol K
66
The difference between the principal specific heats of nitrogen is 300 J/kg-K and the ratio of the two specific heats is 1.4 then:
Cp = 1050 J/kg-K
67
The equation of state corresponding to 8 g of O2 is:
PV = RT/4
68
Cv of gas is 8 calK-1mole-1. Find Cp/Cv. Assume R = 2calK-1mol-1
1.25
69
100g of water is heated from 30°C to 50°C. Ignoring the slight expansion of the water, the change in its internal energy is:
(specific heat of water is 4184 J kg-1 K-1)
8.4 kJ
70
When an ideal diatomic gas is heated at constant pressure, the fraction of the heat energy supplied that increases the internal energy of the gas is:
5/7
71
How much heat is needed to raise the temperature of 100 g of H2O from 22°C to 98°C?
32 kJ
72
A 500-gram cube of lead is heated from 25°C to 75°C. How much energy was required to heat the lead? The specific heat of lead is 0.129 J/g°C
3225 J
73
A closed container contains an ideal gas. Which of the following changes will result in a decrease in temperature?
➡Volume increase
➡Temperture decrease
74
The efficiency of the heat engine can be defined as:
1 - Q2/Q1
75
For an isothermal process, the first law of thermodynamics can be written as:
Heat absorbed = work done by the system
76
Boltzmann's constant k is defined as:
R/N A
77
A liquid has mass m and specific heat capacity c. The rate of change in temperature of the liquid is R. What is the rate at which heat is transferred from the liquid?
Rmc
78
100W heater is used to heat 500g of water from 20°C to 50°C. How long should the heater be switched on?
The specific heat capacity of water is 4.2 J/gC
630 sec
79
The energy input to an engine is 60 J, and the work it performs is 15J. What is its thermal efficiency?
0.25
80
Which of the following is equivalent to a temperature of 150K?
-123°C
81
A monoatomic ideal gas is thermally insulated, so no heat can flow between it and its surroundings. Is it possible for the temperature of the gas to rise?
Yes
➡The temperature can rise if work is done on the gas
82
Some ice, at its melting point, is added to m kg of water at an initial temperature of 290K. if c is the specific heat capacity o water and L is the latent heat of fusion of ice. Ice melts completely. The final temperature of the water is 273 K. What is the minimum mass of ice that is required?
17 mc/L
83
Under what conditions of temperature and pressure do a real gas approximate to an ideal gas?
➡Pressure Low
➡Temperatre High
84
In which process the net work done is zero>
Isochoric
85
Internal energy remains the same throughout the process in:
Isothermal Process
86
An ideal gas is compressed to half of its initial volume. Which of these processes would result in maximum work done>
Adiabatic
87
If the system changes from a state P1 V1 to P2V2 by two paths then the quantity which remains unchanged is:
ΔQ -ΔW
88
An ideal reversible heat engine is 1 efficient only if:
The cold reservoir is at 0K
89
The efficiency of the heat engine in terms of temeprature of reservoir and sink is defined as:
1 - T1/T2
90
According to the first law of thermodynamics;
ΔQ = ΔU + ΔW
91
Which of the following is a thermodynamic coordinate?
R
92
When heat is given to the isobaric process then;
➡Work is done by the gas
➡Internal Energy of gas decreases
93
If N is the number of molecules of gas in a container. Then a number of moles can be calculated as:
N + NA
94
100 W heater is used to melt 50g of ice at 0°C. How long should the heater switch on?
Specific heat latent heat of fusion of ice is 334 J/g.
16.7 min
95
The sum of all forms of molecular energies (kinetic and potential) of a substance is termed as its:
Potential Energy
96
When an ideal gas of constant mass is heated in a container of fixed volume. What is the reason for the increase in pressure of the gas?
Average force per impact at the container wall increases
97
The isothermal process can be defined as:
PV = Constant
98
Which of the following process is irreversible?
A chemical explosion
99
During an adiabatic process, the pressure of the gas is found to be proportional to the fourth power of temperature. The ideal gas would be;
CH2
100
Temperature is defined by:
Zeroth Law of thermodynamics
101
The internal energy of the system depends on:
The path from the initial to the final state
102
The initial mass of water, at its boiling point, is 0.8 kg. 4 kW of the heater is used to boil it completely. Assuming the specific latent heat of vaporization of water in 2MJ/kg. What is the time taken to vaporize all the water?
400sec
103
100 W heater is used for 5 minutes to heat 500g of water. What is the change in the temperature of the water which is heated?
The specific heat capacity of water is 4.2 J/gC
14°C
104
100 W heater is used for 5 minutes to heat some water from 20°C to 50°C. What is the mass of water which is heated?
The specific heat capacity of water is 4.2 J/gC
240 g
105
A car of mass M is moving with speed v. The brake of mass m and specific heat capacity c is used to stop the car. If half of the kinetic energy of the car is absorbed by the brake, then what is the increase in temperature of the brake:
Mv2/4mc
106
If ΔU and ΔW represent internal energy and work done which is true?
ΔU = -ΔW in an adiabaic process
107
The P-V diagram of a diatomic gas is a straight line passing through the origin. What is the molar heat capacity of the gas in the process?
3R
108
What does the constant n represent in the equation of state for an ideal gas PV nRT?
Number of moles of the gas
109
If P=Po and V=Vo gas expands isothermally to P=3Po, then the volume is;
Vo/3
110
Which of the terms is related to thermodynamics?
➡System
➡Boudnary
➡Surrounding
111
The amount of heat supplied to 0.02 kg of nitrogen to raise its temperature by 45° is;
934J
112
What is the internal energy change in a system that has absorbed 800J of heat and work done is 500J?
300J
113
"The heat required to raise the temperature of one mole of the substance through 1K" is called:
Molar specific heat
114
Which of the following is not an assumption o the kinetic model of an ideal gas?
➡Collisions between molecules and walls of the container are elastic❌
➡The duration of collision between molecules is very short❌
➡All particles of gas have the same speed✅
➡All particles of gas have same mass❌
115
The thermodynamics process during which the pressure is kept constant, is called;
Isobaric
116
An ideal gas has a volume of 20ml, a temperature of 10°C and pressure of 100kPa. The volume of the gas is reduced to 10ml and the temperature is raised to 20°C. What is the new pressure of the gas?
207 kPa
117
Two identical gases expand i) isothermally ii) adiabatically. Work done is more in:
Isothermal Process
118
In which of the following processes the heat is neither absorbed nor released by a system?
Adiabatic
119
A heater is used for 5 minutes to heat 500g of water from 20°C to 50°C. What is the power of the heater?
The specific heat capacity of water is 4.2 J/gC
1260 W
120
Which of the following is equivalent to a temperature -50°C?
223K
121
In Boyle's Law, which quantity is constant
T
122
A gas expands from V1 to V2. The amount of work done is greatest in:
Isobaric
123
If heat given is 6kcal and work done is 6kJ, then internal energy is;
19.1 kJ
124
A container is filled with oxygen and helium at the same temperature. The molar mass of oxygen is 32 g/mol and that of helium is 4 g/mol. What is the ratio:
average speed o oxygen molecules _______ average speed o helium molecules?
1/√8
125
How much energy is required to raise the temperature of 5.00 kg of lead from 20.0°C to its melting point of 327°C? The specific heat of lead is 128 J/kg°C
1.96 x 10^5 J
126
In thermodynamics first law is related with;
Energy conservation
127
In the VT diagram slope of the curve is:
nR/P
128
"The amount of heat transfer required to raise the temperature of one mole of the gas through 1K at constant pressure is called:
The molar-specific heat at constant pressure
129
The energy input to an engine is 4.00 times greater than the work it performs. What fraction of the energy input is expelled to the cold reservoir?
0.75
130
100 W heater is switched on for 5 minutes to melt ice. What is the mass of ice that melts at 0°C? Specific latent heat of fusion of ice is 334j/g
90 g
131
In thermodynamics zeroth law is related with:
Therma Equilibrium
132
The value of universal gas, R, the constant is:
8.314 J/mol/K
133
Which of these is constant in the adiabatic process:
➡Total Heat
➡Entropy
134
Which of the following is not an assumption of the kinetic model of an ideal gas?
The kinetic energy of a given particle is the same
135
A cycle tyre bursting suddenly is an example of:
Adiabatic Process
136
300 W heater is used to boil 500g of water at 100°C. How long should the heater switch on? Specific latent heat of vaporization of water is 2230 J/g.
62 mins
137
An ideal gas o N molecule is enclosed in a container at a constant pressure of P. The graph between the volume of gas and its absolute temperature is a straight line. What is the gradient of the graph?
Nk/P
138
The efficiency of the diesel engine is:
35% to 40%
139
The isothermal system has a constant:
Temperature
140
When no heat enters or leaves the system, it is called:
Adiabatic
141
The engine is supposed to work between 727°C and 227°C, the maximum possible efficiency is:
1/2
142
The molar mass of water is:
0.018 kg/mol
143
An ideal gas at 15.5°C and pressure of 1.72x 10^5 Pa occupies a volume of 2.81 m3. How many moles of gas are present
201 mol
144
One kcal =
4180 K
145
If 1 mole of an ideal gas is heated at a constant volume so that its temperature rises by ΔT, then the first law of thermodynamics can be written as:
ΔU = CvΔT
146
A gas expands 0.25m3 at a constant pressure of 10^3 N/m2 then work done is;
250 joules
147
For ideal polyatomic gas molar specific heat is equal to;
24.9 J/mol.K
148
All changes which occur suddenly or which involve friction or dissipation of energy through conduction, convection or radiation are:
Irreversible Changes
149
Which of the following is equivalent to a temperature of -15°C?
123K
150
Which statement is incorrect?
➡In an isobaric process ΔP=0❌
➡In an isothermal process ΔT=0❌
➡In an isochoric process ΔW=0❌
➡In an isothermal process ΔQ=0✅
151
The value of a triple point of water is;
273.16K
152
Under a cyclic path, internal energy after the complete cycle is the same as:
Initial internal energy
153
Initial pressure and volume are P and V respectively. First, it expanded isothermally to 4V and then compressed adiabatically to volume V, the final pressure is;
1P
154
A reversible Carnot engine converts 1/6th of heat into input work then the efficiency of the engine is:
0.166
155
Specific heat o water is:
4180 J/kg.K
156
Two objects, with different sizes, masses, and temperatures are placed in thermal contact. In which direction does the energy travel?
Energy travels from the object at a higher temperature to the object at a lower temperature
157
Area of PV diagram gives:
Work done
158
The first law of thermodynamics is a special case of;
Conservation of energy
159
Work done in an adiabatic process in a gas depends upon;
Change in temperature
160
The energy input to an engine is 60J, and the work it performs is 15J. What reaction of the energy input is expelled to the cold reservoir?
75%
161
The energy input to an engine is 4.00 times greater than the work it performs. What is its thermal efficiency?
0.25
162
The heat reservoir is a ___ temperature bath.
Constant
163
The slope of the adiabatic(ks) and isothermal(kt) curve is related as:
ks = γkt
164
If the heat is absorbed is 10J and Work done is 5J, then the change in internal energy is;
5J
165
A sample of 0.1 g of water at 100°C and normal pressure requires 54 cal of heat energy to convert to steam at 100°C. If the volume of the steam produced is 167.1°C, the change in internal energy of the sample is:
208.6 kJ
166
A monoatomic gas at pressure P and Volume V expands isothermally to volume 2V and then adiabatically to volume 16V. The final pressure is:
P/64
167
When the temperature of the system does not change, it is called:
Isothermal
168
A fraction of internal energy is due to molecular vibration, which is different in different states of matter. Which of the following gives the correct order of a fraction of internal energy due to molecular vibration?
Solid>Liquid>Gas
169
A 1.0 kW heater supplies energy to a liquid of mass 1kg. The temperature of the liquid changes by 80K in a time of 400s. The specific heat capacity of the liquid is 4.0 kJ/kg.K. What is the average power lost by the liquid?
800
170
For an adiabatic process, the first law of thermodynamics can be written as:
Work done by the system = Decrease in internal energy of a system
171
The adiabatic process can be defined as:
PV^γ = Constant
172
During an adiabatic process pressure of a gas is found to be proportional to the cube of its temperature. The ratio of Cp/Cv is:
3/2
173
A reversible Carnot engine converts 1/6th of heat into input work. When the temperature o sink is reduced to 62°C, then efficiency is doubled the temperature of the source and sink is;
99°C, 37°C
174
The sum of all forms of molecular energies of a substance is termed as its:
Internal energy
175
Specific latent heat of fusion of ice is 334 J/g. How much energy decreases by 300J? If at the same time 120J of work is done on the system, find the heat lost by the system.
-420 J
176
An ideal reversible heat engine has:
Highest efficiency
177
What does the constant n represent in the equation of state for an ideal gas PV=nRT?
Number of moles o the gas
178
Which of the following process is reversible?
Isothermal Compression
179
The efficiency of heat engine in terms of the temperature of reservoir and sink is defined as;
1 - T1/T2
180
Which of the terms is related to thermodynamics?
➡System
➡Boundary
➡Surrounding
181
The value of universal gas, R, constant is;
8.3214 J/mol x K
182
Under what conditions of density and pressure does a real gas approximate to an ideal gas?
➡Density low
➡Pressure low
183
Which one of the following is not the unit of heat?
Watt
184
A heat engine performs 100J of work and at the same time rejects 400J of heat energy to the cold reservoirs. What is the efficiency of the engine?
20%
185
The energy input to an engine is 4.00 times greater than the work it performs. What fraction of the energy input is expelled to the cold reservoir?
0.75
186
The value of universal gas, R, constant is;
8.314 J/mol x K
187
A 500 W electric heater is used to heat 1 kg of water without energy losses. The specific heat capacity of water is 4.2 kJ kg K. What is the time taken to heat the water from 25°C to 75°C?
42 seconds
188
A reversible engine works between two temperatures whose difference is 100°C. If it absorbs 746J of heat from the source and rejects 546J to the sink, calculate the temperature of the source and the sink.
100°C, 0°C
189
If for a gas (ΔW=0, ΔQ<0) then;
Pressure decreases
190
Which of the following is not an assumption of the kinetic model of an ideal gas?
Mileculessufer negligible momentum change during wall collisions
191
A monoatomic gas is heated from temperatures T1 and T2 under two different conditions at (i)Constant Volume (ii) Constant Pressure. So change in U is:
Same for both
192
Work done in an adiabatic process of gas from T1 to T2 is:
nR/γ-1 (T1-T2)
193
The increase in temperature of the object is an indication of;
Increase in internal energy
194
100 W heater is used for 5 minutes to heat 500g of water. What is the change in the temperature of the water?
The specific heat capacity of water is 4.2 j/gC.
14°C
195
if 110J heat is added to the system and 40J work is done, then the amount o work done is;
70J
196
An adiabatic change is the one in which:
No heat is added to or taken out of a system
197
Internal energy remains the same throughout the process in:
Isothermal Process
198
The sum of all forms of molecular energies of a substance is termed as its:
Internal energy
199
Qual masses of paraffin and water are mixed in a container of negligible thermal capacity. The initial temperature of the water is 80°C and that of paraffin is 20°. The final temperature of the mixture is:
50°C
200
For a reversible process, a necessary condition is;
The process must be quasistatic
201
If the system goes from two different paths to the same final state, then Q1 and W1 and Q2 and W2 are heat absorbed and work done then:
Q1 - W1 = Q2 - W2
202
A liquid has sepcific heat capcity c. The rate of change in temperature of the liquid is R. The rate at which what is transferred from the liquid is P. What is the mass of the liquid?
P/cR
203
The energy input to an engine is 60J, and the work it performs is 15J. What it's the fraction of the energy input is expelled to the cold reservoir?
75%
204
A temperature of 162°C is equivalent to what temperature in Kelvins?
425K
205
When an ideal gas of constant mass is heated in a container of fixed volume. What is the reason for the increase in pressure of the gas?
Average force per impact at the container wall increases
206
A common material for cushioning objects in packages is made by trapping bubbles of air between sheets of plastic. Is this material more effective at keeping the contents of the package from moving around inside the package?
A hot day
207
Which of this is constant in the isothermal process?
Internal Energy
208
Work done in an isobaric process is given by:
PΔV
209
The energy input to an engine is 4.00 times greater than the work it performs. What fraction of the energy input is expelled to the cold reservoir?
0.75
210
How much energy is required to raise the temperature of 5.00 kg of lead from 20°C to its melting point of 327°C? The specific heat of lead is 128 J/kg.
1.96 x 10^5 J
211
Under which conditions, areal gas approximate to an ideal gas?
Pressure = Low Density = High
212
A refrigerator operates for a certain time, and the work done by the electrical energy during this time is W=1000J. What can be said about the heat delivered to the room containing the refrigerator?
The heat delivered to the room is greater than 1000J
213
Q
The first law of thermodynamics states:
Heat is the form of energy
214
If the temperature of a reservoir of Carnot engine working with efficiency 70% is 1000K, then the temperature of the sink is:
300K
215
A monoatomic gas is supplied to heat Q very slowly keeping the pressure constant. The work done by the gas is:
2Q/5
216
The energy input to an engine is 60J, and the work it performs is 15J. What is its thermal efficiency?
0.25
217
What does the constant N represent in the equation o state for an ideal gas PV=NkT
Number of molecules of gas
218
Work done by bas, pressure and change in volume are related as:
W=PΔV
219
If Q, E and W are the parameters in the cyclic process then:
E=0
220
An ideal gas at 15.5°C and pressure of 1.72 x 10^5 Pa occupies a volume of 2.81 m3. If the volume is raised to 4.16 m3 and the temperature is raised to 28.2°C, what will be the pressure of the gas?
1.21 x 10^5 Pa
221
Which of the following is an example of an isothermal process?
Slow compression or expansion of a gas
222
The work done can also be calculated by:
Area of the curve under the P-V graph
223
What does the constant N represent in the equation of state for an ideal gas PV=NkT?
Number of molecules as
224
Under which conditions, does a real gas approximate an ideal gas?
Pressure = Low Density = Low
225
A fixed mass of gas undergoes isochoric (isovolumetric) change. As a result, the pressure of the gas has increased . Which of the following is true about the gas?
Internal energy= Increase the direction of transfer of thermal energy= Absorbed by the gas
226
Which of the following cannot determine the state of the thermodynamic system?
P and R
227
In adiabatic expansion:
ΔU = negative
228
What is the internal energy change in a system that has absorbed 800J of heat and work done is 500J?
300J
229
In thermodynamics, zeroth law is related with:
Thermal equilibrium
230
When we heat a substance, the energy associated with its atoms or molecules is increased. It means:
Heat is converted to internal energy
231
Two containers hold na ideal gas at the same temperature and pressure. Both containers hold the same type of gas, but container B has twice the volume the container.
What is the average translational kinetic energy per molecule in container B?
Half that of container
232
A cyclic path is one in which the initial state is equal to;
Final state
233
If 1.002 x 10^6 if thermal energy is required to melt some ice at its melting point, what is the mass of ice that melts? Specific latent heat of fusion of ice is 334 J/g
3 kg
234
The turbine in a steam power plant takes steam from a boiler at 427°C and exhausts into a low, temperature reservoir at 77°C. What is the maximum possible efficiency?
50%
235
Which of the following statement is not true about heat engines?
➡All real engines are less efficient than the Carnot engine❌
➡All real engines are less efficient due to friction and heat losses❌
➡Efficiency of Carnot engine working between same two temperatures, depends on the nature of working substance✅
➡The larger the temperature difference between two reservoirs, the greater the efficiency❌
236
The internal energy change in a system that has absorbed 2kcal of heat and done 500J of work is;
7900J
237
The molar-specific heat of a diatomic gas is measured at constant volume and found to be 29.1 J/mol K. What are the types of energy that are contributing to the molar-specific heat?
➡Translation
➡Rotation
➡Vibrational
238
In which process the net work done is zero?
Free Expansion
239
Which of the following is an assumption of the kinetic model of an ideal gas?
The collision between particles is elastic
240
During adiabatic expansion internal energy decreases by 2J, then work done in this process is;
2J
241
Two containers X and Y are filled with an ideal gas. X has 1 mole of gas and Y has 2 moles of gas. The volume of Y is four times that of X. Pressure in Y is half that in X. What is the temperature of the gas in Y _____ temperature of the gas in X
1
242
An ideal gas at 15.5°C and a pressure of 1.72 x 10^5 Pa occupy a volume of 2.81 m3. How many moles o gas are resent?
201 mole
243
An ideal gas at 15.5°C and a pressure of 1.72 x 10^5 Pa occupy a volume of 2.81 m3. If the volume is raised to 4.16 m3 and the temperature is raised to 28.2°C, what will be the pressure of the gas?
1.21 x 10^5 Pa
244
What is the factor upon which the change in internal energy of an ideal gas depends?
Change in temperature
(Change in internal energy of a gas depends upon temperature)
245
The amount of heat required to raise the temperature o 1kg of substance through 1 K is called:
Specific heat Capacity
246
I one mole of an ideal gas is heated at constant pressure, then the first law of thermodynamics can be written as;
CpΔT = CvΔT + PΔV
247
Q
If Cv=5/2 R, Cp will be;
7/2 R
248
The amount of heat required to raise the temperature of 10 moles of water from 70K to 80 K
(molar heat capacity of water is 75.24 J)
7524J
249
The sum of all forms of molecular energies of a substance is termed as;
Internal energy
250
In which process, the entire heat supplied to the gas is converted to internal energy?
Isochoric Process
251
The internal energy of a system during an isothermal process:
Remain Constant
(T∝U)
➡T=Constant, U=Constant
252
In a certain process, 40J of heat energy is supplied to a system and at the same time, 150J of work is done by the system. The increase in internal energy of the system is:
250J
253
The rapid escape of air from a burst tyre is an example of :
Adiabatic
254
Cp - Cv value, find 3 moles of gas gives:
3R
255
Examples of first law of thermodynamcis are:
➡Working of bicycle pump
➡Human metabolism
➡Brakes applied by an automobile
256
The graphical line of isochoric process is parallel to the:
Pressure axis
257
In isothermal process which of the following is not true?
No heat enters or leaves the system
258
First law of thermodynamics for an adiabatic process is:
W = -ΔU
259
The rapid expansion and compression of air thorugh which a sound wave is passing, obeys:
Adiabatic Process
260
If the volume of the gas is to be increased by 4 times , then:
A constant P the temeprature must be increased by four times
261
The cloud formation is the example of;
Adiabtatic Process
262
In realtion PV^γ = constant the γ is given by:
Cp/Cv
263
Compressed air coming out of punctured football becomes cooler because of:
Isothermal Expansion
264
Find the change in internal energy of the system when a system absorbs 2 kilocalorie of heat and at the same time does 500 joule of work:
7900J
265
In a thermodynamic system working susbtance is ideal gas, its internal energy is in the fomr of :
Kinetic Energy only
266
Which of the following statement is correct for any thermodynamic system?
Internal energy and entropy are state function
267
If heat given to a system is 6 kcal and work done is 6kJ. The change in internal energy is:
19.1 kJ
268
the amount of heat required to raise the temeprature of one kg of susbtance thorugh 1 K is called:
Specific Heat
269
For 1 mole of gas the relation PΔV =
RΔT
270
A gas, for which γ is 4/3, is heated at constant pressure. The percentage of heat supplied used for external work is:
25%
271
The diference between the molar specific heat at cosntant pressure and volume is called:
Universal Gas Constant
272
For mono-atomic gas Cv = 3R/2, therefore γ for this gas is:
5/3
273
The unit of moalr specific heat is same as that of:
Molar ideal gas constant
274
110J of heat is added to a gaseous system, whose internal energy change is 40J. then the amount of external work done is:
70J
275
Which of the following can not determine the state of thermodynamic system
Any one of pressure, volume or temperature
276
The specific heats at constant pressure is greater than that of the gas at cosntant volume because:
at constant pressure work is done in expanding the gas
277
If the amount of heat given to a system be 35joules and the amount of work done by the system be 15 joules, then the change in the internal energy of the system is:
20 joules
278
The value of universal gas cosntant R is:
8.314 J mol-1 K-1
279
Which of the following possess maximum root mean square velocity at same temperature?
Hydrogen
280
The average K.E of hydrogen molecules at 300K is E. At same temerature K.E of oxygen molecuels will be:
E
281
Which of the following is not a state function fo a ssytem?
Heat
282
The equation of state for 5 g of oxygen at a pressure P and Temperature T, when occupying a volume V , will be:
PV = (5/32)RT
283
Which of teh following is expression of mean square speed of "N" gas molecuels contained in a cylinder?
V1^2 +V2^2 +Vn^2/N
284
A vessel contains 1 mole of O2 at temperature T. The pressure Is P. An identical vessel containing 1 mole o He gas at a temperature 2T has ap ressure.
2P
285
In the mass of all moelcuels of a gas are halved and their speed is doubled, then the ratio of their initial and final pressure is;
1:2
286
For mono atomic gas Cv = 3/2 R value of Cp is:
5/2 R
287
The temperature of a gas is raised from 27°C to 927°C. The root mean square speed is:
Gets doubled
288
The temperature of a gas is increased from 27°C to 127°C. The ratio of its mean kinetic energies will be:
3/4
289
The volume of a gas will be double of what it is at 0°C at:
273°C
290
The speeds of 5 molecuels of gas are as follows: 2,3,4,5,6
The root mean square speed for these molecuels is:
4.24 m/s
291
Pressure of a gas at constant volume is proportional to:
Kinetic Energy of molecules
292
Two identical sample of a gas are allowed to expand (i) isothermally (ii) adiabatically. Work done is:
More in the isothermal process
293
Mean square velocity of five moelcuels of velocities 2 m/s, 3m/s, 4 m/s, 5m/s and 6 m/s is:
18 m2/s2
294
A gas is taken in a sealed container at 300K. It is heated at cosntatn volume to a temperature 600K. The mean K.E of its molecules is:
Doubled
295
The mean kinetic enrgy of one gram-mole of a perfect gas at absolute temeprature T is:
3/2 RT
296
For hydrogen gas Cp-Cv = a and for oxygen gas Cp-Cv=b, so that relation between a and b is given by:
a= b
297
According to kinetic theory of gases at absolute zero temeprature
Molecuels motion stops
298
If Cp-Cv = R and Cp/Cv = γ, then which relation is correct
Cv = R/γ -1
299
If a cylinder containing a gas at high pressure explodes, the gas undergoes:
➡Irreversible adiabatic change
➡Fall of temeprature
300
Which of the followin is relation for V(r.m.s):
➡√EP/ρ
➡√3RT/M
➡√3kT/M
301
What thermodynamic temeprature is equivalent to 501.85°C?
775.00K
302
Which is called internal energy of an ideal gas?
Translational Kinetic energy
303
Cloud formation in atmosphere is an exampe of :
Adiabatic Process
304
The triple point of water is:
273.16K
305
The temeprature of a gas is increased from 27°C to 127°C. The ratio of its mean kinetic energies will be:
3/4
306
110 Joules of heat are added to a gaseous system, whose internal energy is 40J. The amount of external work done is:
70J
307
A system doe 600J of work at the same time has its internal energy increased by 320J. How much heat is suplied?
920J
308
Gas molecules of different masses in the same container have the same translational kinetic energy. Which is direclty proportional to:
Absolute Temeprature
309
Average translational kinetic energy per molecule of an ideal gas is given by:
3RT/2NA
310
The internal nergy of 1 mole of an ideal gas depends upon:
Only tmeprature
311
The average kinetic energy of hydrogen moelcules at 300K is E. At the same temperature, the average kinetic energy of oxygen moelcules will be:
E
312
If Q is amount of heat added to a system and W is work done by the system, then change in internal nergy can be defined as:
Q-W
313
The rms speed of moelcuels of a gas depends upon:
➡Pressure of gas
➡Temeprature of gas
➡Density of gas
314
Mass (m ) of one molecule of a gas can be written as:
Molecular Mass/NA
315
If the volume of a gas is held constant and we increase its temperature then:
Its Pressure rises
316
At constant pressure the volume of the given mass of a gas is V at temperature T. At what temeprature volume of the gas will be 4V:
4T
317
Which one of the expression is correct for the molar volume V of an ideal gas:
RT/P
318
As Cp-Cv =R shows that Cp> Cv. What is also true?
ΔUp = ΔUv
319
According to the first law of thermodynamcis applied to a gas, the increase in the internal nergy during any process:
Equals the heat input plus the work done on the gas
