Thermodynamics Questions and Answers

lic pro ess as V graph above If the system consists of an ideal gas of n moles What will be the total work done during the cycle TA 2To To B Vo A 2nRT ln 3 0 B 3nRTo In 3 C D 3V0 V

A heat engine goes through one complete cycle arriving back at its initial starting point How has the total thermal energy of the gas changed It depends on the work done The energy has decreased No change

10 A vessel contains 6 g of oxygen at pressure P and temperature 400 K A small hole is made in it so that oxygen leaks out How much oxygen leaks out if final pressure is P 2 and temperature is 300 K NCERT Pg 339 1 5 g 2 3 g 3 2 g 4 4 g 11 If the pressure and volume of a certain quantity of an ideal gas is halved them in 14 A real gas b no 1 Both pre 2 Both pre 3 Pressur 4 Pressur 15 What will b molecule ir pressure a molecule is

39 If the P V diagrams of two thermodynamics devices working in a cyclic process are as shown in the figure then 0 V A 1 A is a heat engine B is a heat pump refrigerator 2 B is a heat engine A is a heat pump refrigerator 3 both A and B are heat engines 4 both A and B are heat pumps refrigerator

Cement is T Pg 327 cules in a iner total is elastic egree of ure only gas gy the do 7 Three moles of oxygen are mixed with two moles of helium what will be approx ratio of specific heat at constant pressure and constant volume for the mixture NCERT Pg 329 1 1 2 2 1 4 3 1 5 4 1 67 8 The kinetic theory of gases gives the formula 1 Nm

In a dairy operation milk at a flow rate of 250 liter hour and a cow body temperature of 58 3 C must be chilled to a safe to store temperature of 17 C or less Ground water at 8 C is available at a flow rate of 0 72 m h The density and specific heat of milk are 1030 kg m and 3860 respectively Determine the heat exchanger effectiveness Select one a 0 74 b 0 93 c 0 87 O d 0 82

15 The molar heat capacity in process of diatomic gas if it does a work when a heat Q is supplied to it is y 7 5 15R 1 4 9R 3 3 2 4 15R 2 9R

For the free expansion of an ideal gas under adiabatic conditions which of the following is true Q W 0 and AU O Q 0 W 0 and AU W Q 0 W 0 and AU W Q0 W0 and AU 0

An ideal gas is taken around the cycle ABCA as shown in the P V diagram The total work done by the gas during the cycle is PV 2PV 4PV P 4P P B A V C 3V V

One mole of an ideal gas at an initial temperature of TK does 15R joules of work adiabatically If the ratio of specific heats of this gas at constan pressure and at constant volume is 5 3 the final temperature of gas will be 1 T 24 K 3 T 4 K 2 T 10 K 4 T 10 K

Q16 An ideal monatomic gas is confined in a horizon tal cylinder by a spring loaded piston as shown in the figure Initially the gas is at temperature T pressure P and volume V and the spring is in its relaxed state The gas is then heated very slowly to temperature T2 pressure p2 and volume V During the process the pis ton moves out by a distance x Ignoring the friction between the piston and the cylinder the correct state ment s is are 2015 mmm A If V 2V and T2 3T1 then the energy stored in the spring is p V B If V 2V and T 37 then the change in internal energy is 3p V C If V 3V and T 4T then the work done by the gas is p V D If V 3V and T 4T then the heat supplied

x10 3 mol of gas undergoes the process shown in the figure gure 1 re p atm 3 2 1 1 of 1 Part C If the constant volume of this process is V 425 cm what is the final temperature Express your answer using three significant figures View Available Hint s VAZO Submit Previous Answers Request Answer X Incorrect Try Again Part D Complete previous part s Part E Complete previous part s K

A step down transformer connected to an ac mains supply of 220 V is made to operate at 11 V 44 WX lamp Ignoring power losses in the transformer what is the current in the primary circuit 4 A 0 2 A 0 4 A 2 A 1 2 3 4 To 220 20 X 220 11V 1

The pressure in a monoatomic gas increases volume increases from Vo to 2Vo The increase in internal energy is P 3P Po Vo O V 2V 15P Vo O 7 5PV B 12 5P Vo

2 13 In the figure shown here the work done in the process ACBA is Pressure 3Po Po 0 eqx9 1 4P Vo A SO B Chidupl Vo Volume 3Vo 0 2 6P Vo 0

Three moles of nitrogen is mixed with six moles of helium The effective molar specific heat of the mixture at constant volume is 1 7 R 1 4 R 1 83 R

One mole of a diatomic gas is taken around a cyclic process shown in the figure The process BC is adiabatic expansion 2P and the process CA is isothermal compression If the volume of the gas at C is given by Vc 2 Vo then the value of n is Po B

2 Carbon monoxide is carried around a P closed cyclic process abc in which be is an isothermal process as shown in figure The gas absorbs 7000 J of heat P as its temperature is increased from 300 K to 1000 K in going from a to b The quantity of heat ejected by the gas during the process ca is 1 4200 J 3 9000 J 2 500 J 4 9800 J V

10 In a mechanical refrigerator the low temperature coils are at a temperature of 23 C and the compressed gas in the condenser has a temperature of 27 C The theoretical coefficient of performance is 1 5 2 8 3 6 A rouonsibl 4 6 5 Sala at input into

3 A thermodynamic process is shown in figure The pressures and volumes corresponding to some points in the figure are P 3 10 Pa Pg 8 10 Pa and V 2 10 m V 5 10 m In process AB 600 J of heat is added to the system and in process BC 200 J of heat is added to the system The change in internal energy of the system in process AC would be 1 560 J 3 600 2 800 J 4 640I

13 The relation between internal energy U pressure P and volume V of a gas in an adiabatic process is U a bPV where a and b are constants What is the effective value of adiabatic constant y 1 a b 3 a 1 2 4 a 4 A diatomic ideal gas is hentar b 1 b b a

9 Heat energy absorbed by a system in going through a cyclic process shown in figure is 1 10 m J 3 10 m J 2 10 J 4 10 J V in litre 30 10 10 P KPa 30

1 5 2 8 3 6 4 6 5 11 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 temperature of the source and sink are 1 80 C 37 C 3 90 C 37 C 2 95 C 28 C 4 99 C 37 C

3 Certain amount of an ideal gas is contained in a closed vessel The vessel is moving with a constant velocity v The molecular mass of gas is M The rise in temperature of the gas when the vessel is suddenly stopped is y Cp Cy 1 3 Mv Y 1 2R Y 1 Mv 2R Y 1 2 Mv y 1 2R 4 Mv 2R Y 1

1 One mole of an ideal monatomic gas requires 210 J heat to raise the temperature by 10 K when heated at constant temperature If the same gas is heated at constant volume to raise the temperature by 10 K then heat required is 1 238 J 3 210 J 2 126 J 4 350 J

The efficiency of a heat engine increases by 20 when temperature of source is increased by 20 and temperature of sink is decreased by 20 simultaneously The old efficiency of the engine is 3 50 4 62 5 1 40 2 42 5 In the arrangement for SHM shown the horizontal ground is smooth and the coefficient of friction between the two blocks is u The time period of oscillation is T The maximum amplitude of vibration so that the two blocks remain together is

1 cm of water at its boiling point absorbs 540 calories of heat to become steam with a volume of 1671 cm If the atmospheric pressure 1 013 x 105 N m and the mechanical equivalent of heat 4 19 J calorie the energy spent in this process in overcoming intermolecular forces is MP PET 1999 2001 Odisha JEE 2002 a 540 cal b 40 cal c 500 cal d zero

while some are process variables Some grouping of the parameters are given Choose the correct one 1 State variables Temperature No of moles Process variables Internal energy work done by the gas 2 State variables Volume Temperature Process variables Internal energy work done by the gas 3 State variables Work done by the gas heat rejected by the gas Process variables Temperature volume 4 State variables Internal operoy volume 1 2 3 3 4 2 the age fa un m gi af RI fel a STA Y f GRI ter fra ary 314 RI MORA

Suppose heat is lost from the lateral surface of a thin rod of length L into a surrounding medium at temperature zero If the linear law of heat transfer applies then the heat equation takes on the form a u au hu 0 x L t 0 at h a constant Find the temperature u x t if the initial temperature is f x throughout and the ends x 0 and x L are insulated insulated 0 insulated 0 heat transfer from lateral surface of the rod X

3 2 1 4 16 1 141 An ideal gas with pressure P volume V and temperature T is expanded isothermally to volume 2V and a final pressure P The same gas is expanded adiabatically to a volume 2V the final pressure is PA In terms of the ratio of the two specific heats for the gas y the ratio P P is 1 2Y 2 2 Y 3 2Y 4 2y 141 1 37f 377 PA PA 1

Select an incorrect statement relating to a Carnot cycle O a Work occurs for all four processes O b There are two adiabatic processes O c There are two constant pressure processes d Each process is a reversible process

Helium is to be compressed from 150 kPa and 360 K to 600 kPa and 500 K A heat loss of 15 kJ kg occurs during the compression process Neglecting kinetic energy changes determine the power input required for a mass flow rate of 60 kg min where the constant pressure specific heat of helium is Cp 5 1926 kJ kg K

Find the instantaneous velocity at t 3 5 s from the graph given below w x 25 50 75 100 125 150 175 1 2 1 4 9 CI Axi B 1 3 t s 2 19 6 4 3 44 1 At 5 6 4 74 4 5 122 5 A 6 176 4

Which of the following is true for a closed system a mass does not enter or leave the system b none of the mentioned c mass entering can be more or less than the mass leaving d mass entering mass leaving

A Carnot cycle is a cycle of special interest because a When it is carefully constructed in a laboratory it provides an upper limit on cycle efficiency O b It operates between two constant temperature thermal reservoirs O c It establishes a lower limit on cycle efficiency O d It provides the maximum efficiency for any cycle

hermodynamic processes are indicated in the following diagram Match the following Column 1 P Process I Q Process II R Process III S Process IV 111 700K 500 K 300 K Column 2 B S A Adiabatic B Isobaric C Isochoric D Isothermal

of an ideal diatomic gas undergoes 34 a transition from A to B along a path AB as shown in the figure Pin kPa 5 EN 2 A 4 Vin m B The change in internal energy of the gas during the transition is 1 20 kJ 2 20 J 4 201 35 3 A of t also

A cylindrical container having non conducting walls is partitioned in two equal parts such that the volume of each part is V Amovable non conducting piston is kept between the two parts Gas on lett is slowly heated so that the gas on right is compressed upto volume Find pressure and temperature on both sides if initial pressure and temperature were P and T respectively Also find heat given by the heater to the gas number of moles in each part is n 0x0000 non conducting walls non conducting movable piston P V T monoatomic werd transfer

16 Heat energy absorbed by a system going through a cyclic process as shown in figure is V litre 30 10 10 1 107 J 30 P kPa 2 10 J 3 10 J 4 10 J

The work done by the system in the cyclic process as show in figure is V cm 500 300 10 J 3 14 J 8 43 J 40 60 P in kPa

An ideal gas undergoes the following process as shown in the figure The same process may be represented by chef zeny zgur A4 95 13 Uca ch fac u uffa fu PA A At E C P C B TA B B T Correct Answer Your Answer B E A TH LA TA B E Correct Answer Your Answer

SolveLancer Test 2 moles of a gas is heated from 27 C to 37 C at constant pressure The amount heat required is 80 cal When the same gas is heated at constant volume to raise its temperature over the same interval at a constant volume find the amount of required heat R2 cal mol K 1 SolveLancer Test a 80 cal b 20 cal c 60 cal d 40 cal

Answer A B Thevenin resistance is found by D Shorting all voltage sources Opening all current sources C Shorting all voltage sources and opening all current sources Opening all voltage sources

The land area required for installation of nuclear power plant is Answer A more than thermal power plant B C D less than thermal power plant equal to thermal power plant depends on type of construction

An ideal gas undergoes a process as shown in the figure At state C 5Vc VA The C pressure of the gas at C is 1 2 X x 10 N m n Find the value of n 5 3 1 G 106 N m ng 43 Ma Afy n PA 10 N m 8 6 4 2 D a 7 teg gymz Yc U A CR 5Vc V 1 A 100 K 7B A 700 K T Correct Answer 03

View in English An ideal gas has 3 rotational degrees of freedom and 3 translational degrees of freedom The ratio of molar specific heat of the gas at constant pressure to that at constant volume will be

1 1 5 x 105 N m 2 3 x 105 N m 3 2 1 x 105 N m 4 In changing the state of a system from state A to state B adiabatically the work done on the system is 322 joule If 100 calories of heat are given to the system in bringing it from state B to state A then the work done on the system in this process will be 1 98 joule 2 38 2 joule 3 15 9 calorie 4 15 9 joule

A fixed mass of a gas is first heated isobarically to double the volume and then cooled isochorically to decrease the temperature back to the initial value By what factor would the work done by the gas decreased had the process of change of state been isothermal Question Type Single Correct Type 1 2 3 2 1 2 In 2

1 5 2 6 3 7 If 1 kg air y 1 4 is heated adiabatically from 0 C to 10 C then increase in its internal energy will be C 0 172 cal gm C 1 1720 joule 2 7224 joule 3 172 calorie 4 7224 calorie UMSI 45

1 3P V 2 3P V 3 6P V 4 12P V The volume of air increases by 5 in its adiabatic expansion The percentage decrease in its pressure will be 1 5 2 6 3 7 4 8 If 1 kg air y 1 4 is heated adiabatically from 0 C to 10 C then increase in its internal energy will b