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 Page 1


JEE Solved Example on Calorimetry and Thermal 
Expansion 
JEE Mains 
Q1: Overall change in volume and radii of a uniform cylindrical steel wire are ?? . ?? % and ?? . ?????? % 
respectively when subjected to some suitable force. Longitudinal tensile stress acting on the wire 
is (?? = ?? . ?? × ????
????
????
-?? ) 
(A) ?? . ?? × ????
?? ????
-?? 
(B) ?? . ?? × ????
?? ????
-?? 
(C) ?? . ?? × ????
?? ????
-?? 
(D) ?? . ???? × ????
?? ????
-?? 
 Ans: (D) ?? = ?? × ?? ?
????
?? =
????
?? +
?? l
l
 ?
0.2
100
= -2 ×
????
?? +
?? l
l
 ?
?? l
l
=
0.2
100
- (
-2 × 0.002
100
)
?? l
l
=
0.2 + 0.004
100
?
0.204
100
 So stress = ?? × strain 
 = 2 × 10
11
×
0.204
100
= 4.08 × 10
8
 N/m
2
.
 
 
Q2: A solid sphere of radius R made of material of bulk modulus ?? is surrounded by a liquid in a 
cylindrical container. A massless piston of area A floats on the surface of the liquid. When a mass 
?? is placed on the piston to compress the liquid, the fractional change in the radius of the sphere 
???? /?? is 
(A) Kmg /A 
(B) ?????? /?? ?? 
(C) ???? /?? 
(D) ???? /?????? 
Ans: (B) 
1
 K
=
-1.?V
V ?p
 and ?P =
mg
A
 So 
??? ?? =
????
?? =
4?? ?? 2
· ????
4?? 3
?? 3
=
3????
?? =
????
3????
=
????
?? 
After correction 
 
Page 2


JEE Solved Example on Calorimetry and Thermal 
Expansion 
JEE Mains 
Q1: Overall change in volume and radii of a uniform cylindrical steel wire are ?? . ?? % and ?? . ?????? % 
respectively when subjected to some suitable force. Longitudinal tensile stress acting on the wire 
is (?? = ?? . ?? × ????
????
????
-?? ) 
(A) ?? . ?? × ????
?? ????
-?? 
(B) ?? . ?? × ????
?? ????
-?? 
(C) ?? . ?? × ????
?? ????
-?? 
(D) ?? . ???? × ????
?? ????
-?? 
 Ans: (D) ?? = ?? × ?? ?
????
?? =
????
?? +
?? l
l
 ?
0.2
100
= -2 ×
????
?? +
?? l
l
 ?
?? l
l
=
0.2
100
- (
-2 × 0.002
100
)
?? l
l
=
0.2 + 0.004
100
?
0.204
100
 So stress = ?? × strain 
 = 2 × 10
11
×
0.204
100
= 4.08 × 10
8
 N/m
2
.
 
 
Q2: A solid sphere of radius R made of material of bulk modulus ?? is surrounded by a liquid in a 
cylindrical container. A massless piston of area A floats on the surface of the liquid. When a mass 
?? is placed on the piston to compress the liquid, the fractional change in the radius of the sphere 
???? /?? is 
(A) Kmg /A 
(B) ?????? /?? ?? 
(C) ???? /?? 
(D) ???? /?????? 
Ans: (B) 
1
 K
=
-1.?V
V ?p
 and ?P =
mg
A
 So 
??? ?? =
????
?? =
4?? ?? 2
· ????
4?? 3
?? 3
=
3????
?? =
????
3????
=
????
?? 
After correction 
 
Q3:  A cylindrical wire of radius ?? ???? , length ?? ?? , Young's modulus = ?? × ????
????
????
?? , Poisson's 
ratio ?? = ?? /???? is stretched by a force of ?????? ?? . Its radius will become 
(A) ?? . ?????????? ???? 
(B) ?? . ?????????? ???? 
(C) ?? . ?????????? ???? 
(D) ?? . ?????????? ???? 
Ans: (D) Stress = ?? × Strain 
 ? Strain = Stress /?? =
100
?? ?? 2
×
1
2 × 10
11
=
1
2 × 10
9
× 3.14 × 10
-6
 =
1
6.28 × 10
3
=
10
6.28
× 10
-4
= 1.6 × 10
-4
 
Now, ?? ·
dl
l
=
-dr
r
? dr = -1 mm× ?? ×
dl
l
 
=
-1.6 × 10
-4
× 3.14
10
, ?? - ?? 0
= -5.024× 10
-5
 
 
 
Q4: A block of mass ?? . ?? ???? is heated to a temperature of ??????
°
?? and placed a large ice block. What 
is the maximum amount of ice that can melt (approx.)? Specific heat for the body = ?? . ???????? /????
°
?? . 
(A) ?? ???? 
(B) ?? . ?? ???? 
(C) ?? ???? 
(D) ?? . ?? ???? 
Ans: (B) 2.5 × 10
3
gm· (0.1cal/gm
°
C) · (500- 0) 
 = m × L
 ?
2.5 × 100× 0.1 × 500
80
= m.
 = 1.5625× 10
3
 g
 
 
Q?? :  ?? ???? of ice at- ????
°
?? is mixed with ?? . ?? ???? of water at ????
°
?? . The final temperature of mixture 
is: (specific heat of ice is ???????? ?? /???? /?? ) 
(A) ?? . ?? °
?? 
(B) ?? . ?? °
?? 
(C) ?? . ?? °
?? 
(D) ?? . ?? °
?? 
Ans: (D) 1cal = 4.2 J 
 ? Specific heat of ice =
21000
42
cal/Kg· K
 = 500cal /kg. K = 0.5cal/gm· K
 
Page 3


JEE Solved Example on Calorimetry and Thermal 
Expansion 
JEE Mains 
Q1: Overall change in volume and radii of a uniform cylindrical steel wire are ?? . ?? % and ?? . ?????? % 
respectively when subjected to some suitable force. Longitudinal tensile stress acting on the wire 
is (?? = ?? . ?? × ????
????
????
-?? ) 
(A) ?? . ?? × ????
?? ????
-?? 
(B) ?? . ?? × ????
?? ????
-?? 
(C) ?? . ?? × ????
?? ????
-?? 
(D) ?? . ???? × ????
?? ????
-?? 
 Ans: (D) ?? = ?? × ?? ?
????
?? =
????
?? +
?? l
l
 ?
0.2
100
= -2 ×
????
?? +
?? l
l
 ?
?? l
l
=
0.2
100
- (
-2 × 0.002
100
)
?? l
l
=
0.2 + 0.004
100
?
0.204
100
 So stress = ?? × strain 
 = 2 × 10
11
×
0.204
100
= 4.08 × 10
8
 N/m
2
.
 
 
Q2: A solid sphere of radius R made of material of bulk modulus ?? is surrounded by a liquid in a 
cylindrical container. A massless piston of area A floats on the surface of the liquid. When a mass 
?? is placed on the piston to compress the liquid, the fractional change in the radius of the sphere 
???? /?? is 
(A) Kmg /A 
(B) ?????? /?? ?? 
(C) ???? /?? 
(D) ???? /?????? 
Ans: (B) 
1
 K
=
-1.?V
V ?p
 and ?P =
mg
A
 So 
??? ?? =
????
?? =
4?? ?? 2
· ????
4?? 3
?? 3
=
3????
?? =
????
3????
=
????
?? 
After correction 
 
Q3:  A cylindrical wire of radius ?? ???? , length ?? ?? , Young's modulus = ?? × ????
????
????
?? , Poisson's 
ratio ?? = ?? /???? is stretched by a force of ?????? ?? . Its radius will become 
(A) ?? . ?????????? ???? 
(B) ?? . ?????????? ???? 
(C) ?? . ?????????? ???? 
(D) ?? . ?????????? ???? 
Ans: (D) Stress = ?? × Strain 
 ? Strain = Stress /?? =
100
?? ?? 2
×
1
2 × 10
11
=
1
2 × 10
9
× 3.14 × 10
-6
 =
1
6.28 × 10
3
=
10
6.28
× 10
-4
= 1.6 × 10
-4
 
Now, ?? ·
dl
l
=
-dr
r
? dr = -1 mm× ?? ×
dl
l
 
=
-1.6 × 10
-4
× 3.14
10
, ?? - ?? 0
= -5.024× 10
-5
 
 
 
Q4: A block of mass ?? . ?? ???? is heated to a temperature of ??????
°
?? and placed a large ice block. What 
is the maximum amount of ice that can melt (approx.)? Specific heat for the body = ?? . ???????? /????
°
?? . 
(A) ?? ???? 
(B) ?? . ?? ???? 
(C) ?? ???? 
(D) ?? . ?? ???? 
Ans: (B) 2.5 × 10
3
gm· (0.1cal/gm
°
C) · (500- 0) 
 = m × L
 ?
2.5 × 100× 0.1 × 500
80
= m.
 = 1.5625× 10
3
 g
 
 
Q?? :  ?? ???? of ice at- ????
°
?? is mixed with ?? . ?? ???? of water at ????
°
?? . The final temperature of mixture 
is: (specific heat of ice is ???????? ?? /???? /?? ) 
(A) ?? . ?? °
?? 
(B) ?? . ?? °
?? 
(C) ?? . ?? °
?? 
(D) ?? . ?? °
?? 
Ans: (D) 1cal = 4.2 J 
 ? Specific heat of ice =
21000
42
cal/Kg· K
 = 500cal /kg. K = 0.5cal/gm· K
 
So suppose the mixture is at temperature ?? , then 
?? ?? · ?? ?? · (??? ) + ?? ?? ?? = +?? ?? · ?? ?? (?? - 0)
 = ?? ?? · ?? ?? (30 - ?? )
 ? 1000× 0.5 × 10 + 80 × 1000+ 1000× 1 × ?? = 4400× 1 × (30 - ?? )
 ? 5000+ 80000+ 1000 T
 = 4400× 30 - 4400 T
 ? 5400 T = 47000
 ? T = 8.7
°
C
 
 
 
 
Q6:  Steam at ??????
°
?? is added slowly to ???????????? of water at ????
°
?? , until the temperature of water 
is raised to ????
°
?? . The mass of steam required to do this is (?? ?? = ???????????? /???? ): 
(A) ?????????? 
(B) ?????????? 
(C) ?????????? 
(D) ?????????? 
 Ans: (?? )???? ??? = ?? ?? · ?? ?? ? 1400× 1 × 64 = ?? × 540
 
 
 
Q7:  Ice at ?? °
?? is added to ?????? ?? of water initially at ????
°
?? in a vacuum flask. When ???? ?? of ice has 
been added and has all melted the temperature of the flask and contents is ????
°
?? . When a further 
???? ?? of ice has been added and has all melted, the temperature of the whole is ????
°
?? . Calculate the 
specific latent heat of fusion of ice. [? Takes  
?? = ???????? /????
°
?? ] 
(A) ?? . ?? × ????
?? ?? /???? 
(B) ?? . ?? × ????
?? ?? /???? 
(C) ?? . ?? × ????
?? ?? /???? 
(D) ?? . ?? × ????
?? ?? /???? 
Ans: (A) Let the heat capacity of the flask be M 
Then ?? = latent heat of fusion 
 Then 50?? + 50(40 - 0) = 200× (70 - 40) + (70 - 40) × ?? ? 50?? + 2000= 6000+ 30M
 ? 5?? = 3?? + 400
 
And 80 L + 80(10 - 0) = 250× (40 - 10) + ?? (30) 
Page 4


JEE Solved Example on Calorimetry and Thermal 
Expansion 
JEE Mains 
Q1: Overall change in volume and radii of a uniform cylindrical steel wire are ?? . ?? % and ?? . ?????? % 
respectively when subjected to some suitable force. Longitudinal tensile stress acting on the wire 
is (?? = ?? . ?? × ????
????
????
-?? ) 
(A) ?? . ?? × ????
?? ????
-?? 
(B) ?? . ?? × ????
?? ????
-?? 
(C) ?? . ?? × ????
?? ????
-?? 
(D) ?? . ???? × ????
?? ????
-?? 
 Ans: (D) ?? = ?? × ?? ?
????
?? =
????
?? +
?? l
l
 ?
0.2
100
= -2 ×
????
?? +
?? l
l
 ?
?? l
l
=
0.2
100
- (
-2 × 0.002
100
)
?? l
l
=
0.2 + 0.004
100
?
0.204
100
 So stress = ?? × strain 
 = 2 × 10
11
×
0.204
100
= 4.08 × 10
8
 N/m
2
.
 
 
Q2: A solid sphere of radius R made of material of bulk modulus ?? is surrounded by a liquid in a 
cylindrical container. A massless piston of area A floats on the surface of the liquid. When a mass 
?? is placed on the piston to compress the liquid, the fractional change in the radius of the sphere 
???? /?? is 
(A) Kmg /A 
(B) ?????? /?? ?? 
(C) ???? /?? 
(D) ???? /?????? 
Ans: (B) 
1
 K
=
-1.?V
V ?p
 and ?P =
mg
A
 So 
??? ?? =
????
?? =
4?? ?? 2
· ????
4?? 3
?? 3
=
3????
?? =
????
3????
=
????
?? 
After correction 
 
Q3:  A cylindrical wire of radius ?? ???? , length ?? ?? , Young's modulus = ?? × ????
????
????
?? , Poisson's 
ratio ?? = ?? /???? is stretched by a force of ?????? ?? . Its radius will become 
(A) ?? . ?????????? ???? 
(B) ?? . ?????????? ???? 
(C) ?? . ?????????? ???? 
(D) ?? . ?????????? ???? 
Ans: (D) Stress = ?? × Strain 
 ? Strain = Stress /?? =
100
?? ?? 2
×
1
2 × 10
11
=
1
2 × 10
9
× 3.14 × 10
-6
 =
1
6.28 × 10
3
=
10
6.28
× 10
-4
= 1.6 × 10
-4
 
Now, ?? ·
dl
l
=
-dr
r
? dr = -1 mm× ?? ×
dl
l
 
=
-1.6 × 10
-4
× 3.14
10
, ?? - ?? 0
= -5.024× 10
-5
 
 
 
Q4: A block of mass ?? . ?? ???? is heated to a temperature of ??????
°
?? and placed a large ice block. What 
is the maximum amount of ice that can melt (approx.)? Specific heat for the body = ?? . ???????? /????
°
?? . 
(A) ?? ???? 
(B) ?? . ?? ???? 
(C) ?? ???? 
(D) ?? . ?? ???? 
Ans: (B) 2.5 × 10
3
gm· (0.1cal/gm
°
C) · (500- 0) 
 = m × L
 ?
2.5 × 100× 0.1 × 500
80
= m.
 = 1.5625× 10
3
 g
 
 
Q?? :  ?? ???? of ice at- ????
°
?? is mixed with ?? . ?? ???? of water at ????
°
?? . The final temperature of mixture 
is: (specific heat of ice is ???????? ?? /???? /?? ) 
(A) ?? . ?? °
?? 
(B) ?? . ?? °
?? 
(C) ?? . ?? °
?? 
(D) ?? . ?? °
?? 
Ans: (D) 1cal = 4.2 J 
 ? Specific heat of ice =
21000
42
cal/Kg· K
 = 500cal /kg. K = 0.5cal/gm· K
 
So suppose the mixture is at temperature ?? , then 
?? ?? · ?? ?? · (??? ) + ?? ?? ?? = +?? ?? · ?? ?? (?? - 0)
 = ?? ?? · ?? ?? (30 - ?? )
 ? 1000× 0.5 × 10 + 80 × 1000+ 1000× 1 × ?? = 4400× 1 × (30 - ?? )
 ? 5000+ 80000+ 1000 T
 = 4400× 30 - 4400 T
 ? 5400 T = 47000
 ? T = 8.7
°
C
 
 
 
 
Q6:  Steam at ??????
°
?? is added slowly to ???????????? of water at ????
°
?? , until the temperature of water 
is raised to ????
°
?? . The mass of steam required to do this is (?? ?? = ???????????? /???? ): 
(A) ?????????? 
(B) ?????????? 
(C) ?????????? 
(D) ?????????? 
 Ans: (?? )???? ??? = ?? ?? · ?? ?? ? 1400× 1 × 64 = ?? × 540
 
 
 
Q7:  Ice at ?? °
?? is added to ?????? ?? of water initially at ????
°
?? in a vacuum flask. When ???? ?? of ice has 
been added and has all melted the temperature of the flask and contents is ????
°
?? . When a further 
???? ?? of ice has been added and has all melted, the temperature of the whole is ????
°
?? . Calculate the 
specific latent heat of fusion of ice. [? Takes  
?? = ???????? /????
°
?? ] 
(A) ?? . ?? × ????
?? ?? /???? 
(B) ?? . ?? × ????
?? ?? /???? 
(C) ?? . ?? × ????
?? ?? /???? 
(D) ?? . ?? × ????
?? ?? /???? 
Ans: (A) Let the heat capacity of the flask be M 
Then ?? = latent heat of fusion 
 Then 50?? + 50(40 - 0) = 200× (70 - 40) + (70 - 40) × ?? ? 50?? + 2000= 6000+ 30M
 ? 5?? = 3?? + 400
 
And 80 L + 80(10 - 0) = 250× (40 - 10) + ?? (30) 
 ? 80 L + 800 = 7500+ 30M
 ? 8 L = 3M + 670
 ? 8 L = 5 L - 400 + 670
 ? L = 90cal/gm
 ? 90 × 4.2 × 10
3
 J/kg = 3.8 × 10
5
 J/Kg
 
 
 
Q8:  A continuous flow water heater (geyser) has an electrical power rating = ?????? and efficiency 
of conversion of electrical power into heat = ???? %. If water is flowing through the device at the 
rate of ?????????? / ?????? , and the inlet temperature is ????
°
?? , the outlet temperature will be. 
(A) ???? . ?? °
?? 
(B) ???? . ?? °
?? 
(C) ????
°
?? 
(D) ????
°
?? 
 Ans: (B) 
????
????
= 100 cm
3
/sec
 ?
????
????
= ?? ·
????
????
= 100gm /sec.
 
Now, power used in heating = 2000× 0.8 = 1600 W. 
Now, power =
d(ms?T)
dt
= s. ?T.
dm
dt
 
Now assuming ??? is same 
 So 1600=
100
1000
kg
sec
× 4200
J
kg · K
× ?T
 ?
1600× 10
4200
= ?T = 3.8
°
C.
 ? T - 10
°
= 3.8
°
? T = 13.8
°
C(B)
 
 
Q9: A steel tape gives correct measurement at ????
°
?? . A piece of wood is being measured with the 
steel tape gives correct measurement at ????
°
?? . A piece of wood is being measured with the steel 
tape at ?? °
?? . The reading is ???? ???? on the tape, The real length of the given piece of wood must be: 
(A) ???? ???? 
(B) < ???? ???? 
(C) > ???? ???? 
(D) Cannot say 
Ans: (B) Refer theory 
 
 
 
Page 5


JEE Solved Example on Calorimetry and Thermal 
Expansion 
JEE Mains 
Q1: Overall change in volume and radii of a uniform cylindrical steel wire are ?? . ?? % and ?? . ?????? % 
respectively when subjected to some suitable force. Longitudinal tensile stress acting on the wire 
is (?? = ?? . ?? × ????
????
????
-?? ) 
(A) ?? . ?? × ????
?? ????
-?? 
(B) ?? . ?? × ????
?? ????
-?? 
(C) ?? . ?? × ????
?? ????
-?? 
(D) ?? . ???? × ????
?? ????
-?? 
 Ans: (D) ?? = ?? × ?? ?
????
?? =
????
?? +
?? l
l
 ?
0.2
100
= -2 ×
????
?? +
?? l
l
 ?
?? l
l
=
0.2
100
- (
-2 × 0.002
100
)
?? l
l
=
0.2 + 0.004
100
?
0.204
100
 So stress = ?? × strain 
 = 2 × 10
11
×
0.204
100
= 4.08 × 10
8
 N/m
2
.
 
 
Q2: A solid sphere of radius R made of material of bulk modulus ?? is surrounded by a liquid in a 
cylindrical container. A massless piston of area A floats on the surface of the liquid. When a mass 
?? is placed on the piston to compress the liquid, the fractional change in the radius of the sphere 
???? /?? is 
(A) Kmg /A 
(B) ?????? /?? ?? 
(C) ???? /?? 
(D) ???? /?????? 
Ans: (B) 
1
 K
=
-1.?V
V ?p
 and ?P =
mg
A
 So 
??? ?? =
????
?? =
4?? ?? 2
· ????
4?? 3
?? 3
=
3????
?? =
????
3????
=
????
?? 
After correction 
 
Q3:  A cylindrical wire of radius ?? ???? , length ?? ?? , Young's modulus = ?? × ????
????
????
?? , Poisson's 
ratio ?? = ?? /???? is stretched by a force of ?????? ?? . Its radius will become 
(A) ?? . ?????????? ???? 
(B) ?? . ?????????? ???? 
(C) ?? . ?????????? ???? 
(D) ?? . ?????????? ???? 
Ans: (D) Stress = ?? × Strain 
 ? Strain = Stress /?? =
100
?? ?? 2
×
1
2 × 10
11
=
1
2 × 10
9
× 3.14 × 10
-6
 =
1
6.28 × 10
3
=
10
6.28
× 10
-4
= 1.6 × 10
-4
 
Now, ?? ·
dl
l
=
-dr
r
? dr = -1 mm× ?? ×
dl
l
 
=
-1.6 × 10
-4
× 3.14
10
, ?? - ?? 0
= -5.024× 10
-5
 
 
 
Q4: A block of mass ?? . ?? ???? is heated to a temperature of ??????
°
?? and placed a large ice block. What 
is the maximum amount of ice that can melt (approx.)? Specific heat for the body = ?? . ???????? /????
°
?? . 
(A) ?? ???? 
(B) ?? . ?? ???? 
(C) ?? ???? 
(D) ?? . ?? ???? 
Ans: (B) 2.5 × 10
3
gm· (0.1cal/gm
°
C) · (500- 0) 
 = m × L
 ?
2.5 × 100× 0.1 × 500
80
= m.
 = 1.5625× 10
3
 g
 
 
Q?? :  ?? ???? of ice at- ????
°
?? is mixed with ?? . ?? ???? of water at ????
°
?? . The final temperature of mixture 
is: (specific heat of ice is ???????? ?? /???? /?? ) 
(A) ?? . ?? °
?? 
(B) ?? . ?? °
?? 
(C) ?? . ?? °
?? 
(D) ?? . ?? °
?? 
Ans: (D) 1cal = 4.2 J 
 ? Specific heat of ice =
21000
42
cal/Kg· K
 = 500cal /kg. K = 0.5cal/gm· K
 
So suppose the mixture is at temperature ?? , then 
?? ?? · ?? ?? · (??? ) + ?? ?? ?? = +?? ?? · ?? ?? (?? - 0)
 = ?? ?? · ?? ?? (30 - ?? )
 ? 1000× 0.5 × 10 + 80 × 1000+ 1000× 1 × ?? = 4400× 1 × (30 - ?? )
 ? 5000+ 80000+ 1000 T
 = 4400× 30 - 4400 T
 ? 5400 T = 47000
 ? T = 8.7
°
C
 
 
 
 
Q6:  Steam at ??????
°
?? is added slowly to ???????????? of water at ????
°
?? , until the temperature of water 
is raised to ????
°
?? . The mass of steam required to do this is (?? ?? = ???????????? /???? ): 
(A) ?????????? 
(B) ?????????? 
(C) ?????????? 
(D) ?????????? 
 Ans: (?? )???? ??? = ?? ?? · ?? ?? ? 1400× 1 × 64 = ?? × 540
 
 
 
Q7:  Ice at ?? °
?? is added to ?????? ?? of water initially at ????
°
?? in a vacuum flask. When ???? ?? of ice has 
been added and has all melted the temperature of the flask and contents is ????
°
?? . When a further 
???? ?? of ice has been added and has all melted, the temperature of the whole is ????
°
?? . Calculate the 
specific latent heat of fusion of ice. [? Takes  
?? = ???????? /????
°
?? ] 
(A) ?? . ?? × ????
?? ?? /???? 
(B) ?? . ?? × ????
?? ?? /???? 
(C) ?? . ?? × ????
?? ?? /???? 
(D) ?? . ?? × ????
?? ?? /???? 
Ans: (A) Let the heat capacity of the flask be M 
Then ?? = latent heat of fusion 
 Then 50?? + 50(40 - 0) = 200× (70 - 40) + (70 - 40) × ?? ? 50?? + 2000= 6000+ 30M
 ? 5?? = 3?? + 400
 
And 80 L + 80(10 - 0) = 250× (40 - 10) + ?? (30) 
 ? 80 L + 800 = 7500+ 30M
 ? 8 L = 3M + 670
 ? 8 L = 5 L - 400 + 670
 ? L = 90cal/gm
 ? 90 × 4.2 × 10
3
 J/kg = 3.8 × 10
5
 J/Kg
 
 
 
Q8:  A continuous flow water heater (geyser) has an electrical power rating = ?????? and efficiency 
of conversion of electrical power into heat = ???? %. If water is flowing through the device at the 
rate of ?????????? / ?????? , and the inlet temperature is ????
°
?? , the outlet temperature will be. 
(A) ???? . ?? °
?? 
(B) ???? . ?? °
?? 
(C) ????
°
?? 
(D) ????
°
?? 
 Ans: (B) 
????
????
= 100 cm
3
/sec
 ?
????
????
= ?? ·
????
????
= 100gm /sec.
 
Now, power used in heating = 2000× 0.8 = 1600 W. 
Now, power =
d(ms?T)
dt
= s. ?T.
dm
dt
 
Now assuming ??? is same 
 So 1600=
100
1000
kg
sec
× 4200
J
kg · K
× ?T
 ?
1600× 10
4200
= ?T = 3.8
°
C.
 ? T - 10
°
= 3.8
°
? T = 13.8
°
C(B)
 
 
Q9: A steel tape gives correct measurement at ????
°
?? . A piece of wood is being measured with the 
steel tape gives correct measurement at ????
°
?? . A piece of wood is being measured with the steel 
tape at ?? °
?? . The reading is ???? ???? on the tape, The real length of the given piece of wood must be: 
(A) ???? ???? 
(B) < ???? ???? 
(C) > ???? ???? 
(D) Cannot say 
Ans: (B) Refer theory 
 
 
 
Q10:  A metallic rod ?? ???? long with a square crosssection is heated through ?? °
?? . If Young's 
modulus of elasticity of the metal is ?? and the mean coefficient of linear expansion is ?? per degree 
Celsius, then the compressional force required to prevent the rod from expanding along its length 
is: (Neglect the change of cross-sectional area) 
(A) EA ?? ?? 
(B) EA ???? (?? + ???? ) 
(C) ???????? (?? - ???? ) 
(D) ?? /???? 
Ans: (B) Actual length = ?? 0
(?? + ?? ??? ) = ?? 0
(1 + ???? ) 
Change in length = ?? 0
(1 + ?? t) - ?? 0
= ?? 0
???? 
So strain =
?? 0
????
?? 0
(1+?? t)
=
?? t
(1+?? t)
 
? Stress = E × strain =
E?? t
(1+?? t)
 
? Force = A × stress =
EA?? t
1+?? t
 
 
Q11: A solid ball is completely immersed in a liquid. The coefficient of volume expansion of the ball 
and liquid are ?? × ????
-?? and ?? × ????
-?? per  
°
?? respectively. The percentage change in upthrust 
when the temperature is increased by ??????
°
?? is. 
(A) ?? . ?? % 
(B) ?? . ???? % 
(C) ?? . ?? % 
(D) ?? . ???? % 
Ans: (D) ?? l
(t) · V
s
(t) · g =
?? l
(1+8×10
-6
×10
2
)
 
 × v
s
(1 + 3 × 10
-6
× 10
2
) × g
 = ?? l
v
s
· g · (1 + 3 × 10
-4
)(1 - 8 × 10
-4
)
 so difference = ?? l
· v
?? · ?? (-5 × 10
-4
)
 
 
Q12:  70 cal of heat are required to raise the temperature of 2 mole of an ideal diatomic gas at 
constant pressure from ????
°
?? . The amount of heat required (in calorie) to raise the temperature of 
the same gas through the same range (????
°
?? to ????
°
?? ) at constant volume is. 
(A) 30 
(B) 50 
(C) 70 
(D) 90 
 Ans: (B) Q
1
= nC
p
?T, Q
2
= nC
v
?T,
Q
2
Q
1
=
?? ?? ?? ?? =
1
?? or Q
2
=
Q
1
?? =
70
1.4
= 50cal
 
 
 
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FAQs on Solved Example: Calorimetry and Thermal Expansion - Physics for JEE Main & Advanced

1. What is calorimetry and how is it used in thermal expansion?
Ans. Calorimetry is the science of measuring heat transfer in a system. It is used in thermal expansion to study how materials expand or contract with changes in temperature.
2. How does calorimetry help in determining the specific heat capacity of a substance?
Ans. Calorimetry involves measuring the heat exchange between a substance and its surroundings. By analyzing this heat transfer along with the mass and temperature change of the substance, the specific heat capacity can be determined.
3. Can calorimetry be used to study the thermal expansion of different materials?
Ans. Yes, calorimetry can be used to study the thermal expansion of various materials by measuring the heat flow associated with their expansion or contraction as they are heated or cooled.
4. What are the applications of calorimetry and thermal expansion in real life?
Ans. Calorimetry and thermal expansion are used in various industries such as construction, automotive, and aerospace to design materials that can withstand temperature changes without failure.
5. How can calorimetry and thermal expansion experiments be conducted in a laboratory setting?
Ans. Calorimetry and thermal expansion experiments can be conducted in a laboratory using calorimeters and equipment to measure temperature changes, heat flow, and thermal expansion of materials under controlled conditions.
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