QUESTION FOR SHORT ANSWER
Q.1 Can one object be hotter thananother if theyare at thesame temperature? Explain.
Q.2 What qualities makeaparticularthermometricpropertysuitableforuseinapractical thermometer?
Q.3 Youputtwouncovered pails ofwater, one containing hot waterand onecontainingcold water,outside
inbelow-freezingweather.Thepailwiththehotwaterwillusuallybegintofreezefirst.Why?Whatwould
happen if youcovered the pails?
Q.4 Can atemperature be assigned to a vacuum?
Q.5 Whatarethedimensionsof,thecoefficientoflinearexpansion?Doesthevalueofdepend ontheunit
oflengthused? When Fahrenheit degreesare used insteadofCelsius degrees as theunit oftemperature
change, does the numerical value of  change? If so, how? If not, prove it.
Q.6 Ametal ball can pass through a metal ring. When the ball is heated, however, it gets stuck in the ring.
What wouldhappen if the ring, rather than the ball, were heated?
Q.7 Twostrips,oneofironandoneofzinc,arerivetedtogethersidebysideto form astraightbarthat curves
when heated.Whyis the ironon the inside ofthe curve?
Q.8 Explainhowtheperiodofapendulumclockcan bekept constantwith temperaturebyattachingvertical
tubes ofmercuryto the bottom ofthe pendulum.
Q.9 What causes water pipes to burst in the winter?
Q.10 Dothepressureandvolumeofairinahousechangewhenthefurnaceraisesthetemperaturesignificantly?
If not,is the ideal gas lawviolated?
Q.11 Iftwosystemsareinthermal equilibrium,theyhavethesametemperature. Istheconversetrue? Thatis,
iftwosystemshavethesametemperature,aretheyinthermalequilibrium? What can yousayabout two
systems thathavedifferent temperatures?
Q.12 As a practical matter, there is always a temperature difference between a system and some part of its
environment,howeverremote.Must therealways besomeheat transferred becauseofthat temperature
difference?Explain.

Q.9 Asteel tapegives correct measurement at20°C.Apiece of wood is being measured with the steel tape
at 0°C. The readingis 25 cm on the tape, the real length ofthe given piece of wood must be:
(A) 25 cm (B) <25 cm (C) >25 cm (D) can not say
Q.10 A rod of length 20 cm is made of metal. It expands by0.075 cm when its temperature is raised from
0°C to 100°C.Another rod of a different metal B having the same length expands by0.045 cm for
the same change in temperature, a third rod of the same length is composed of two parts one of
metalAand the other of metal B. Thus rod expand by 0.06 cm.for the same change in temperature.
The portion made of metalAhas the length :
(A) 20 cm (B) 10 cm (C) 15 cm (D) 18 cm
Q.11 Asphere ofdiameter7 cm and mass 266.5 gm floats in a bath ofa liquid.As the temperature is raised,
thespherejustbegins tosinkatatemperature35°C.Ifthedensityofaliquid at 0°C is1.527 gm/cc,then
neglectingtheexpansionofthesphere,thecoefficient ofcubical expansion oftheliquidisf:
(A) 8.486 × 104
per 0
C (B) 8.486 × 105
per 0
C
(C) 8.486 × 106
per 0
C (D) 8.486 × 103
per 0
C
Q.12 The volume of the bulb ofa mercurythermometerat 0°C isV0
and cross section of thecapillaryisA0
.
Thecoefficient oflinearexpansion ofglass is ag
per°C andthecubical expansionof mercurym
per°C.
If themercuryjust fills thebulb at 0°C, what is thelength ofmercurycolumn incapillaryat T°C.
(A)
 
 
T
2
1
A
3
T
V
g
0
g
m
0
a
a



(B)
 
 
T
2
1
A
3
T
V
g
g
m
a
a
0
0



(C)
 
 
T
3
1
A
2
T
V
g
g
m
a
a
0
0



(D)
 
 
T
3
1
A
2
T
V
g
g
m
a
a
0
0



Q.13 Ametallic rod l cm long with a square cross-section is heated through 1°C. IfYoung’s modulus of
elasticityofthemetal is Eandthe meancoefficient oflinearexpansion is perdegreeCelsius,then the
compressional forcerequiredtoprevent therodfrom expandingalongits lengthis :(Neglectthechange
of cross-sectional area)
(A) EAt (B) EAt/(1 + t) (C) EAt/(1t) (D) E/t
Q.14 Thelossinweightofasolidwhenimmersedinaliquidat0°CisW0
andat t°CisW.Ifcubicalcoefficient
of expansion of the solid and the liquid by S
and 1
respectively, then W is equal to :
(A) W0
[1 + ( s
– l
) t] (B) W0
[1 - (s
– l
)t]
(C) W0
[( s
– l
) t] (D) W0
t/(s
– l
)
Q.15 A thin walled cylindrical metal vessel of linear coefficient of expansion 10–3
°C–1
contains benzenr of
volume expansion coefficient 10–3
°C–1
. If the vessel and its contents are now heated by 10°C, the
pressure due to the liquid at the bottom.
(A) increases by2% (B) decreases by 1% (C) decreases by 2% (D)remainsunchanged
Q.16 A rod of length 2m at 0°C and having expansion coefficient  = (3x + 2) × 10–6
°C–1
where x is the
distance (in cm) from one end of rod. The length of rod at 20°C is :
(A) 2.124 m (B) 3.24 m (C) 2.0120 m (D) 3.124 m
Q.17 Acopper ring has a diameter of exactly 25 mm at its temperature of 0°C.An aluminium sphere has a
diameter ofexactly25.05 mm at its temperature of 100°C. The sphere is placed on top of thering and
two are allowedto come to thermal equilibrium, no heat beinglost to the surrounding.The sphere just
passes throughthe ringat theequilibrium temperature. The ratioofthemass ofthe sphere & ringis :
(given : Cu
= 17 × 10–6
/°C, Al
= 2.3 × 10–5
/°C, specific heat of Cu = 0.0923 Cal/g°C and specific
heat ofAl = 0.215 cal/g°C)
(A) 1/5 (B) 23/108 (C) 23/54 (D) 216/23

Question No. 27 to 31 (5 question)
Solids andliquidsbothexpandonheating.Thedensityofsubstancedecreases on expanding according
totherelation
)
T
T
(
1 1
2
1
2






where, 1 — densityat T1
2 — density at T2
 —coeff. of volumeexpansion of substances
whenasolidissubmergedinaliquid, liquidexertsanupwardforceonsolidwhichisequalto theweight
of liquiddisplaced bysubmergedpart of solid.
Solidwillfloat orsink dependsonrelativedensities ofsolidand liquid.
Acubicalblockofsolidfloatsinaliquidwithhalfofits volumesubmerged in liquid asshownin figure
(at temperature T)
S — coeff.oflinear expansion ofsolid
L — coeff.ofvolumeexpansion ofliquid
S — densityofsolid at temp. T
L — densityofliquid at temp. T
Q.27 Therelationbetweendensities ofsolid and liquidat temperatureT is
(A) S = 2L (B) S = (1/2)L (C) S = L (D) S = (1/4)L
Q.28 Iftemperatureofsystemincreases, thenfraction ofsolid submergedin liquid
(A)increases (B) decreases (C)remains the same (D)inadequateinformation
Q.29 ImaginefractionsubmergeddoesnotchangeonincreasingtemperaturetherelationbetweenL andS is
(A) L = 3S (B) L = 2S (C) L = 4S (D) L = (3/2)S
Q.30 Imaginethedepthoftheblocksubmerged in theliquiddoes not changeonincreasing temperature then
(A) L = 2 (B) L = 3 (C) L = (3/2) (D) L = (4/3)
Q.31 Assume block does not expand on heating. The temperature at which the block just begins to sink in
liquidis
(A) T + 1/L (B) T + 1/(2L) (C) T + 2/L (D) T + L/2
Q.32 The coefficient ofapparent expansion of aliquid in a coppervessel is C and in a silver vessel is S. The
coefficient ofvolume expansionof copperis c. What is thecoefficientoflinearexpansionofsilver?
(A)
( )
C S
c
 

3
(B)
( )
C S
c
 

3
(C)
( )
C S
c
 

3
(D)
( )
C S
c
 

3
Q.33 An aluminium container of mass 100 gm contains 200 gmof ice at –20°C. Heat is addedto the system
at the rateof 100 cal/s. Thetemperature of the system after 4 minutes will be (specific heat ofice = 0.5
and L= 80 cal/gm, specific heat ofAl = 0.2 cal/gm/°C)
(A) 40.5°C (B) 25.5°C (C) 30.3°C (D) 35.0°C

Q.44 Twoverticalglasstubesfilledwithaliquidareconnectedbyacapillary
tube as shown in the figure. The tube on the left is put in an ice bath at
0°C while the tube on the right is kept at 30°C in a water bath. The
difference in the levels of the liquid in the two tubes is 4 cm while the
heightoftheliquidcolumnat 0°Cis 120cm.Thecoefficientofvolume
expansionofliquidis (Ignoreexpansionofglass tube)
(A) 22 × 10–4/°C (B) 1.1 × 10–4/°C
(C) 11 × 10–4/°C (D) 2.2 × 10–4/°C
Q.45 Asystem S receives heat continuouslyfrom an electrical heater of power 10W.The temperature of S
becomes constant at 50°C when the surrounding temperature is 20°C.After the heater is switched off,
S cools from 35.1°C to 34.9°C in 1 minute. The heat capacityof S is
(A) 100J/°C (B) 300J/°C (C) 750J/°C (D) 1500J/°C
Q.46 Ablockofice with mass mfalls intoalake.After impact, a massof ice m/5 melts.Both theblock of ice
and thelakehave atemperatureof 0°C. If Lrepresents theheat offusion, theminimum distancethe ice
fellbeforestrikingthesurfaceis
(A)
g
5
L
(B)
g
L
5
(C)
m
5
gL
(D)
g
5
mL
Q.47 Pure water super cooled to 15°C is contained in a thermally insulated flask. Small amount of ice is
thrown intotheflask. Thefractionofwaterfrozen intoice is :
(A) 3/35 (B) 6/35 (C) 6/29 (D) 2/35
Q.48 The specific heat of a metal at low temperatures varies accordingto S = aT3 where a is a constant and
T is the absolute temperature. The heat energy needed to raise unit mass of the metal from
T = 1 K to T = 2 K is
(A) 3 a (B)
4
a
15
(C)
3
a
2
(D)
5
a
12
Q.49 Thegraphshowninthefigurerepresent changeinthetemperatureof5
kg of a substance as it abosrbs heat at a constant rate of 42 kJ min–1.
The latent heat of vapourazationof thesubstanceis :
(A) 630 kJ kg–1
(B) 126 kJ kg–1
(C) 84 kJ kg–1
(D) 12.6 kJ kg–1
Q.50 The densityof amaterialAis 1500 kg/m3 and that of anothermaterial B is 2000 kg/m3. It is found that
the heat capacityof 8 volumes ofAis equal to heat capacityof 12 volumes of B.The ratio of specific
heats ofAand B will be
(A) 1 : 2 (B) 3 : 1 (C) 3 : 2 (D) 2 : 1
Q.51 Find the amount of heat supplied to decrease thevolume of an ice watermixtureby1 cm3 withoutany
change in temperature. (ice = 0.9 water, Lice = 80 cal/gm).
(A) 360 cal (B) 500 cal (C) 720 cal (D) none of these

Q.59 Two sheets of thickness d and 2d and same area are touchingeach otheron their face.
TemperatureTA,TB,TC shown are in geometric progressionwith common ratio r= 2.
Thenratioofthermal conductivityofthinnerandthickersheet are
(A) 1 (B) 2 (C) 3 (D) 4
Q.60 Thewallwithacavityconsistsoftwo layersofbrickseparated byalayerofair.Allthreelayershavethe
samethicknessandthethermal conductivityofthebrickismuch greaterthan thatofair.Theleftlayeris
at a higher temperature than the right layer and steadystate condition exists. Which of the following
graphs predicts correctlythe variationof temperatureT with distanced insidethecavity?
(A) (B) (C) (D)
Q.61 Awall has twolayerAand B eachmadeof different material, boththe layers have the same thickness.
ThethermalconductivityofthematerialAis twicethatofB.Underthermalequilibrium thetemperature
difference across the wall B is 36°C.The temperature difference across thewallAis
(A) 6°C (B) 12°C (C) 18°C (D) 72°C
Q.62 Aringconsistingof twopartsADBandACBof sameconductivityk carries an
amount of heat H.TheADB part is now replaced with another metal keeping
the temperatures T1
and T2
constant. The heat carried increases to 2H. What
should be the conductivityofthe newADB part? Given
ADB
ACB
= 3:
(A)
3
7
k (B) 2 k (C)
2
5
k (D) 3 k
Q.63 Threeconductingrodsofsamematerialandcross-sectionareshowninfigure.
Temperatures ofA, D and C are maintained at 20°C, 90°C and 0°C. The
ratioof lengths of BD and BC if thereis no heat flow inAB is:
(A) 2 / 7 (B) 7 / 2 (C) 9 / 2 (D) 2 / 9
Q.64 Threerodsmadeofthesamematerial and havingsamecross-sectional areabut
different lengths 10cm,20cm and30cm arejoinedasshown. Thetemperature
ofthejointis:
(A) 20°C (B) 23.7°C (C) 16.4°C (D) 18.2°C
Q.65 Twelveconductingrodsform theridersofauniformcubeofside'l'.Ifin
steady state, B and H ends of the rod are at 100°C and 0°C. Find the
temperature ofthe junction 'A'.
(A) 80°C (B) 60°C (C) 40°C (D) 70°C
Q.66 Sixidenticalconductingrodsarejoinedasshowninfigure.PointsAand
D aremaintained at temperature of 200°C and 20°C respectively.The
temperatureofjunctionBwillbe:
(A) 120°C (B) 100°C (C) 140°C (D) 80°C

Q.74 If TA and TB are the temperature drops across the rodAand B, then
(A)
B
A
T
T
=
1
3
(B)
B
A
T
T
=
3
1
(C)
B
A
T
T
=
4
3
(D)
B
A
T
T
=
3
4
Q.75 If GA and GB are the temperature gradients across the rodAand B, then
(A)
B
A
G
G
=
1
3
(B)
B
A
G
G
=
3
1
(C)
B
A
G
G
=
4
3
(D)
B
A
G
G
=
3
4
Q.76 Twosheets ofthicknessdand3d,aretouchingeachother.Thetemperaturejust outsidethethinnersheet
side isA, and on the side of the thicker sheet is C. The interface temperature is B.A, B and C are in
arithmeticprogressing, theratioofthermalconductivityofthinnersheetandthickersheetis
(A) 1 : 3 (B) 3 : 1 (C) 2 : 3 (D) 1 : 9
Q.77 Acylindricalrodwithoneendinasteamchamberandtheouterendiniceresultsinmeltingof0.1gmofice
persecond.Iftherodisreplacedbyanotherwithhalfthelengthanddoubletheradiusofthefirstandifthe
thermalconductivityofmaterialofsecondrodis1/4thatoffirst,therateatwhichicemeltsisgm/secwillbe
(A) 3.2 (B) 1.6 (C) 0.2 (D) 0.1
Q.78 A composite rodmadeof threerods of equal length and cross-section as shown in the fig. The thermal
conductivities of the materials of the rods are K/2, 5K and K respectively. The endAand end B are at
constanttemperatures.AllheatenteringthefaceAgoes outofthe end Btherebeingnolossof heat from
thesides of thebar.Theeffective thermal conductivityofthebar is
B
A
K
5K
K/2
(A) 15K/16 (B) 6K/13 (C) 5K/16 (D) 2K/13.
Q.79 A rod of length L with sides fully insulated is of a material whose thermal conductivity varies with
temperature as K=
T

, where  is a constant. The ends of the rod are kept at temperature T1
and T2
.
The temperature T at x, where x is the distance from the end whose temperature is T1
is
(A)
L
x
1
2
1
T
T
T 







(B)
1
2
T
T
n
L
x
l (C) L
T
x
T
1
1
2
e
T (D) x
L
T
T
T 1
2
1


Q.80 The power radiatedbya black bodyis P and it radiates maximum energyaround the wavelength 0
. If
thetemperatureoftheblackbodyisnowchangedsothatitradiatesmaximumenergyaroundwavelength
3/40
, the power radiated byit will increase bya factor of
(A) 4/3 (B) 16/9 (C) 64/27 (D) 256/81
Q.81 A black metalfoil is warmed byradiation from a small sphere at temperature 'T' and at a distance 'd'.
It is foundthat thepowerreceivedbythefoil isP . Ifboththe temperature and distancearedoubled, the
power receivedbythe foil will be :
(A) 16 P (B) 4 P (C) 2 P (D) P

ONE OR MORE THAN ONE OPTION MAY BE CORRECT
Take approx. 3 minutes for answering each question.
Q.1 Four rodsA,B,C, Dof samelengthandmaterial but ofdifferent radii r, 2
r , 3
r and 2r respectively
are held betweentwo rigid walls. Thetemperature of all rods is increased bysame amount. If the rods
donot bend, then
(A) the stress in the rods are in the ratio 1 : 2 : 3 : 4.
(B) the force on the rod exerted bythe wall are in the ratio 1 : 2 : 3 : 4.
(C) the energystored in the rods due to elasticityare in the ratio 1 : 2 : 3 : 4.
(D) the strains produced in the rods are in the ratio 1 : 2 : 3 : 4.
Q.2 AbodyofmassM isattachedtothelowerendofametal wire,whoseupperendisfixed.Theelongation
of thewire is l.
(A)Loss ingravitational potential energyofM is Mgl
(B)The elasticpotential energystoredin thewire is Mgl
(C) The elastic potential energystored in the wire is 1/2 Mgl
(D) Heat produced is 1/2 Mgl.
Q.3 When the temperature of a copper coin is raised by80°C, its diameter increases by0.2%.
(A) Percentage rise in the area of a face is 0.4 %
(B) Percentage rise in the thickness is 0.4 %
(C) Percentagerise in the volume is 0.6 %
(D) Coefficient of linear expansion of copper is 0.25 × 10–4 C° –1.
Q.4 An experiment is perfomed to measure the specific heat of copper.Alump of copper is heated in an
oven, then dropped into a beaker of water. To calculate the specific heat of copper, the experimenter
must know ormeasure the value of all of the quantities belowEXCEPT the
(A) heat capacityof water and beaker
(B) original temperature of the copperand the water
(C) final (equilibrium)temperature ofthe copperand thewater
(D) time takento achieve equilibrium afterthe copper is dropped into the water
Q.5 One end of a conducting rod is maintained at temperature 50°C and at the other end, ice is melting at
0°C.The rateofmeltingoficeis doubled if:
(A) the temperature is made 200°C and the area of cross-section of the rod is doubled
(B) the temperatureis made 100°C andlength of rod is made four times
(C) areaof cross-section of rodis halved and length is doubled
(D) the temperature is made 100°C and the area of cross-section of rod and length both are doubled.
Q.6 Twometallic sphereAandB aremade ofsamematerial andhavegot identical surfacefinish.Themass
of sphereAis four times thatof B. Both thespheres are heated to the same temperature and placed in a
room havinglowertemperaturebut thermallyinsulatedfromeachother.
(A) The ratio of heat loss ofAto that of B is 24/3.
(B) The ratio of heat loss ofAto that of B is 22/3.
(C)The ratio of the initial rate of cooling ofAto that of B is 2-2/3.
(D)The ratio of the initial rate of cooling ofAto that of B is 2-4/3.

Answer Key
ONLY ONE OPTION IS CORRECT.
Q.1 E Q.2 B Q.3 D Q.4 A Q.5 B Q.6 B Q.7 C
Q.8 C Q.9 B Q.10 B Q.11 A Q.12 B Q.13 B Q.14 A
Q.15 C Q.16 C Q.17 C Q.18 C Q.19 D Q.20 C Q.21 D
Q.22 B Q.23 C Q.24 B Q.25 A Q.26 C Q.27 B Q.28 A
Q.29 A Q.30 A Q.31 A Q.32 C Q.33 B Q.34 A Q.35 B
Q.36 D Q.37 A Q.38 D Q.39 A Q.40 C Q.41 B Q.42 A
Q.43 D Q.44 C Q.45 D Q.46 A Q.47 B Q.48 B Q.49 C
Q.50 D Q.51 C Q.52 A Q.53 C Q.54 A Q.55 C Q.56 D
Q.57 B Q.58 B Q.59 A Q.60 D Q.61 C Q.62 A Q.63 B
Q.64 C Q.65 B Q.66 C Q.67 B Q.68 C Q.69 C Q.70 A
Q.71 A Q.72 A Q.73 A Q.74 B Q.75 B Q.76 A Q.77 C
Q.78 A Q.79 A Q.80 D Q.81 B Q.82 A Q.83 C Q.84 B
Q.85 D Q.86 B Q.87 B Q.88 B Q.89 A
ONE OR MORE THAN ONE OPTION MAY BE CORRECT
Q.1 B,C Q.2 A,CD Q.3 A,C,D Q.4 D
Q.5 D Q.6 A,C Q.7 A,B Q.8 D
Q.9 A,B Q.10 A,B,C,D Q.11 B