ANSWERS TO MULTIPLE CHOICE QUESTIONS: 6.

Consider the following statement:

STATEMENT – I: Steel is preferred over copper and aluminium in structural designs.
1 2 3 4 5 6 7 8 9 10 STATEMENT – II: Steel is more elastic than copper and aluminium as its Young’s modulus is
greater than that for copper and aluminium.
C C B D B B A A A C Among the given two statements:
11 12 13 14 15 16 17 18 19 20 (A) Both statements are correct and statement – II is the correct reason for statement – I.
(B) Both statements are correct but statement – II is not a correct reason for statement – I.
C C D A C D A B D B (C) Statement – I is correct but statement – II is wrong.
(D) Both statements are wrong.
ANSWERS TO FIBS:
7. The approximate relationship between Young’s modulus and rigidity modulus is:
1. maximum, 2. zero, 3.time period, 4. linear momentum, 4. energy (A) ≈ (B) ≈ (C) ≈ (D) ≈
*************************************************************************************** 8. Which one of the following correctly represents the general relationship between bulk moduli (B)
of solids, liquids and gases?
(A) < < (B) > =
(C) = > (D) > >
9. The Young’s modulus of a perfect rigid body is:
(A) zero (B) infinite (C) 0.5 Pa (D) negative
8. MECHANICAL PROPERTIES OF SOLIDS 10. If is the stress in a stretched wire and ε is the corresponding strain, the elastic energy density in
the wire is given by:
MULTIPLE CHOICE QUESTIONS: (A) = (B) = (C) = (D) =
1. The breaking stress of a wire depends upon: 11. Consider the following statement:
(A) length of the wire (B) the radius of the wire STATEMENT – I: To avoid buckling of beams, load-bearing bars of I – section are used.
(C) the material of the wire (D) shape of the area of cross-section of the wire. STATEMENT – II: Bars of I – shape provide large load bearing surface and good strength with
2. The SI unit and the dimensional formula for modulus of elasticity are: less weight.
(A) Pa, [ML2T-2] (B) Nm-2, [ML-1T-2] (C) Pa, [ML1T-2] (D) N, [ML-1T-2] Among the given two statements:
3. The following table lists several points relates to the given (A) Both statements are correct and statement – II is the correct.
stress-strain curve and the corresponding names. Match (B) Statement – II is correct but statement – I is wrong
column – I with correct option among column – II. (C) Statement – I is correct but statement – II is wrong.
(D) Both statements are wrong.
Column – I Column – II 12. Within proportionality limit, the slope of stress – strain curve gives:
(a) Point A (p) Measure of ductility of the material (A) Modulus of elasticity
(b) Point B (q) Proportionality limit (B) Compressibility
(C) Ultimate tensile stress
(c) Point E (r) Fracture point
(D) Reciprocal of modulus of elasticity
(d) Region DE (s) Yield Point
13. The stress-strain graphs for materials A and B are shown in the figure.
(A) (a) → (q), (b) → (s), (c) → (r), (d) → (p)
(B) (a) → (s), (b) → (q), (c) → (r), (d) → (p)
(C) (a) → (q), (b) → (s), (c) → (p), (d) → (r)
(D) (a) → (s), (b) → (q), (c) → (p), (d) → (r)
4. The stress that changes the volume of the object without changing its shape is:
(A) compressive stress (B) tensile stress The graphs are drawn to the same scale. Then:
(C) shear stress (D) hydraulic stress (A) Material B has greater Young’s modulus
5. After what point on the stress – strain curve for a metal, does the strain keeps increasing even by (B) Material A is more brittle.
a reduced applied force? (C) Material A is stronger than B
(A) Yield point (B) Ultimate tensile strength (D) Both materials are equally ductile.
(C) Fracture point (D) Proportional limit
14. Which one of the following statements is wrong? 3. Derive an expression for elastic potential energy in a stretched wire.
(A) The stretching of a coil is determined by its shear modulus. 4. A steel rod of radius 10 mm and length 2 m is stretched by a force of 100 kN along its length. The
(B) The Young’s modulus of rubber is greater than that of steel. elongation in the wire is 3.2 mm. Find the stress and Young’s modulus of the material of the rod.
(C) When a spring is stretched by applying a load to one of its free ends, both longitudinal and shear [3.2 × 108 Pa, 2 × 1011 Pa]
strains are produced in the spring. 5. The upper face of a cube of edge 1m moves through a distance of 1 mm relative to the lower fixed
(D) Poisson’s ratio is the ratio of lateral strain to the longitudinal strain. surface under action of a tangential force 1.5 × 108 N. Calculate tangential stress and rigidity modulus.
15. The maximum load a wire can withstand without breaking, when its length is reduced to half of [150 MPa, 150 GPa]
its original length, will 6. A square lead slab of side 50 cm and thickness 10 cm subjected to shearing force of 9 × 104 N. How
(A) doubled (B) half (C) four times (D) remain same much will the upper edge be displaced? Shear modulus of lead =5.6 GPa. [0.16 mm]
7. When a rubber ball is taken in deep of 100 m in sea its volume is decrease by 0.1% due to hydraulic
FILL IN THE BLANKS: stress. If the density of seawater is 1000 kgm-3, calculate the bulk modulus and compressibility of the
(Poisson ratio, Young’s modulus, Shear modulus, Compressibility, Bulk modulus) rubber. [9.8 × 108 Pa, 10-9 Pa-1]
1. The ratio between longitudinal stress and longitudinal strain is called ___________. 8. A steel wire of length 5 m and cross section 3 × 10-5 m2 stretched by the same amount as copper of
2. ____________ is the shear stress per unit shear strain. length 3.7 m and cross section 4 × 10-5 m2 under given load. Find the ratio of Young’s modulus of steel
3. Lateral strain = ____________ × Longitudinal strain. to that of copper. [1.8]
4. The reciprocal of bulk modulus is called _____________. 9. The average depth of Indian Ocean is about 3000 m. Calculate the fractional compression, ΔV/V, of
water at the bottom of the ocean, given that the bulk modulus of water is 2.2 × 109 N m–2. (Take g = 10
TWO MARK QUESTIONS: m s–2) [1.36%]
1. What do you mean by elasticity and plasticity? 10. A steel cable with a radius of 1.5 cm supports a chairlift at a ski area. If the maximum stress is not to
2. Give one example each for elastic and plastic substance. exceed 108 N m–2, what is the maximum load the cable can support? [0.71 Kn]
3. Define stress. Mention its SI unit. 11. A rigid bar of mass 15 kg is supported symmetrically by three wires each 2.0 m long. Those at each end
4. Define strain. What is its unit? are of copper and the middle one is of iron. Determine the ratios of their diameters if each is to have the
5. State and explain Hooke’s law. same tension. (Young’s modulus for iron and copper are 190 GPa and 110 GPa respectively) [1.31]
6. Define (i) compressive stress and (ii) tensile stress. 12. Determine the volume contraction of a solid copper cube, 10 cm on an edge, when subjected to a
7. Define (i) shearing stress and (ii) hydraulic stress. hydraulic pressure of 7.0 × 106 Pa. [– 0.05 cm3]
8. Define longitudinal strain. Write the expression for it.
9. Define shearing strain. Write an expression for it. ANSWERS TO MULTIPLE CHOICE QUESTIONS:
10. Define volume strain. Write an expression for it.
11. What is yield point? Define yield strength of a material. 1 2 3 4 5 6 7 8
12. What are elastomers? Give an example. C B A D B A C D
13. Draw stress – strain curve for an elastomer.
14. Write the expression for Young`s modulus. Explain the terms. 9 10 11 12 13 14 15
15. Write the expression for rigidity modulus of the material. Explain the terms. B D A A C B D
16. Mention the expression for bulk modulus of the material. Explain the terms.
17. Write two application of elastic behavior of the material.
18. Define compressibility. Mention its SI unit.
19. Define Poisson ratio. Give an example for it. ANSWERS TO FIBS:
20. Write the expression for the buckling sag of a beam that is supported at its two ends and is loaded at the 1. Young’s modulus; 2. shear modulus; 3. poisson ratio; 4. compressibility
center. Explain the terms.
21. A steel rod of area of cross section 3.14 × 10-4 m2 is stretched by a force of 100 kN. Calculate the stress
acting on the rod. [3.2 × 108 Pa] **************************************************************************
22. Calculate the fractional change in the volume of glass sphere when subjected to a hydraulic pressure of
1.013 × 106 Nm-2. (Bulk modulus of glass is 3.7 × 1010 Nm-2) [0.0027%]
23. The bulk modulus of a material is 2 × 109 Pa. What is its compressibility? [5 × 10-10 Pa-1]

THREE MARK QUESTIONS:

1. Draw typical stress – strain graph for copper. Represent yield point, elastic limit and fracture point.
2. Define (i) Young’s modulus (ii) Rigidity modulus and (iii) Bulk modulus.
 9. MECHANICAL PROPERTIES OF FLUIDS 10. SI unit and dimensional formula for surface tension is:
(A) N m-1, [ML-1T-2] (B) N m, [MT-2] (C) N m-1, [MT-2] (D) J m2, [MT-2]
11. Let θ be the angle of contact between a liquid drop and a solid surface. Then:
(A) The liquid wets the surface if θ > 90° (B) The liquid wets the surface if θ = 90°
MULTIPLE CHOICE QUESTIONS: (C) The liquid wets the surface if θ < 90° (D) The liquid does not wet the surface if θ > 90°
1. Which one of the following statements is wrong? 12. Which one of the following statements is correct?
(A) Solids have a definite shape while liquids and gases do not have definite shape. (A) Hydrostatic pressure is a vector quantity.
(B) The volume of any substance depends on the pressure acting on it. (B) Surface tension of a liquid is independent of the area of the surface.
(C) Solids and liquids have lower compressibility when compared to gases. (C) Water with detergent dissolved in it should has large angles of contact.
(D) When compared to solids, fluids offer large shear stress. (D) Liquids like water, alcohol are more viscous than blood, glycerine, etc.
2. Consider the following two statements: 13. Bernoulli’s principle is:
STATEMENT – I: A sharp needle when pressed against our skin pierces it. (A) the law of conservation of energy for an incompressible, non-viscous fluid.
STATEMENT – II: Smaller the area on which the force acts, greater is the pressure. (B) the law of conservation of energy for an compressible, viscous fluid.
Between the above two statements: (C) the law of conservation of mass for an incompressible, non-viscous fluid.
(A) Both statements are correct and statement – II is the correct reason for statement – I. (D) the law of conservation of momentum for an incompressible, non-viscous fluid.
(B) Both statements are correct but statement – II is not a correct reason for statement – I. 14. The principle behind continuity equation for flow of incompressible fluids is:
(C) Statement – I is correct but statement – II is wrong. (A) the law of conservation of energy (B) the law of conservation of momentum
(D) Both statements are wrong. (C) the law of conservation of mass (D) Pascal’s law
3. The pressure in a fluid at rest is the same at all points if they are at the same height. This is the 15. As the temperature of a water inside a glass capillary tube increases, the height of water in the
statement of: capillary tube (neglect the thermal expansions):
(A) Bernoulli’s principle (B) Pascal’s law (A) increases (B) decreases
(C) Stoke’s law (D) Hooke’s law (C) remains the same (D) may increase or decrease
4. If the area of cross-section of a tube of flow decreases, then the rate of flow of the fluid through it:
FILL IN THE BLANKS
(A) increases (B) remains constant
(turbulent, hydraulic lift, viscosity, dynamic lift, surface tension, open tube manometer)
(C) decreases (D) may increase or decrease
5. When a tank is open to the atmosphere, the speed of efflux is given by (symbols have usual 1. Drops and bubbles are spherical because of their____________ property.
meanings): 2. With increase in temperature, __________ of gases increases.
3. Beyond a limiting value, called critical speed, this flow of a fluid becomes __________.
(A) = 2 ℎ (B) = ℎ (C) = (D) = 4. The force that acts on a body, such as airplane wing, by virtue of its motion through a fluid is
6. Dynamic lift due to spinning is called: called________.
(A) Pascal’s law (B) Magnus effect (C) surface tension (D) viscosity 5. A _________ works on the principle of Pascal’s law.
7. For a given fluid in laminar flow, at a particular temperature, the shearing stress is:
(A) directly proportional to strain (B) directly proportional to (strain)2 TWO MARK QUESTIONS:
1. What are fluids? Give an example.
(C) directly proportional to strain rate (D) inversely proportional to strain rate
8. When an rain drop falls through the atmosphere from a large height: 2. Define pressure. Write its unit.
(A) the net force on it remains constant (B) the net force on it decreases as it falls 3. Define (i) density and (ii) relative density.
(C) the net force on it increases as it falls (D) the drop undergoes continuous retardation 4. Write the equation for gauge pressure and explain the terms.
9. Consider the following two statements: 5. Write the expression for absolute pressure and explain the terms.
STATEMENT – I: No two streamlines can cross each other. 6. State and explain Pascal’s law.
STATEMENT – II: If two streamlines intersect, an oncoming fluid particle can go either one way 7. Mention any two factors on which pressure inside a fluid depends.
or the other and the flow would not be steady. 8. Write the conversion factors of (i) 1 torr and (ii) 1 bar into pascals.
Between the above two statements: 9. In what fields the units torr and bar are used to measure pressure?
(A) Both statements are correct and statement – II is the correct reason for statement – I. 10. What is the use of a (i) mercury barometer and (ii) open tube manometer?
(B) Both statements are correct but statement – II is not a correct reason for statement – I. 11. Write any two applications of Pascal’s law.
(C) Statement – I is correct but statement – II is wrong. 12. What is streamline motion? Give an example
(D) Both statements are wrong. 13. What is turbulent motion? Give an example.
14. What are the limitations of Bernoulli’s equation?
15. Write any two applications of Bernoulli’s principle. 9. A U-tube contains water and methylated spirit separated by mercury. The mercury columns in the two
16. What are (i) Dynamic lift and (ii) Magnus effect? arms are in level with 10.0 cm of water in one arm and 12.5 cm of spirit in the other. What is the relative
17. What is viscosity? Write the expression for coefficient of viscosity. density (also called specific gravity) of spirit? [0.8]
18. Write the SI unit and dimensional formula for coefficient of viscosity. 10. A U-shaped wire is dipped in a soap solution, and removed. The thin soap film formed between the wire
19. State Stoke’s law. Write the expression for the viscous drag force on a spherical object moving through and the light slider supports a weight of 1.5 × 10–2 N (which includes the small weight of the slider).
a fluid. The length of the slider is 30 cm. What is the surface tension of the film? [2.5 × 10-2 N m-1]
20. What are the factors on which drag force on an object moving through a fluid depends?
21. Define the terms (i) surface energy and (ii) surface tension. FIVE MARK QUESTIONS:
22. (i) Why are drops and bubbles spherical in shape? 1. State and prove Bernoulli’s principle.
(ii) Why are detergents used as wetting agents? 2. What is capillarity? Arrive at the expression for capillary rise inside a capillary tube.
23. Write the expression for capillary rise inside a capillary tube. Explain the terms. 3. In a test experiment on a model aeroplane in a wind tunnel, the flow speeds on the upper and lower
24. Mention the expressions for excess pressure inside (i) a drop and (ii) a bubble. surfaces of the wing are 70 m s–1and 63 m s-1 respectively. What is the lift on the wing if its area is 2.5
25. The two thighbones (femurs), each of cross-sectional area 10 cm2 support the upper part of a human m2? Take the density of air to be 1.3 kg m–3. [1.5 × 103 N]
body of mass 40 kg. Estimate the average pressure sustained by the femurs. [2 × 105 Pa] 4. The cylindrical tube of a spray pump has a cross-section of 8.0 cm2 one end of which has 40 fine holes
26. A 50 kg girl wearing high heel shoes balances on a single heel. The heel is circular with a diameter 1.0 each of diameter 1.0 mm. If the liquid flow inside the tube is 1.5 m min–1, what is the speed of ejection
cm. What is the pressure exerted by the heel on the horizontal floor? [6.24 MPa] of the liquid through the holes? [0.637 m s-1]
27. What is the pressure on a swimmer 10 m below the surface of a lake? [Nearly 2 atm]
28. The density of the atmosphere at sea level is 1.29 kg/m3. Assume that it does not change with altitude. ANSWERS TO MULTIPLE CHOICE QUESTIONS:
Then how high would the atmosphere extend? [ 8 km]
29. The terminal velocity of a copper ball of radius 2.0 mm falling through a tank of oil is 6.5 cm s-1.
Compute the viscosity of the oil. Density of oil is 1.5 ×10 kg m , density of copper is 8.9 × 10 kg m-3.
3 -3 3 1 2 3 4 5 6 7 8
[0.99 kg m-1 s-1] D A C B A B C B
30. What is the excess pressure inside the drop of mercury of radius 3.00 mm at room temperature?
Surface tension of mercury at that temperature (20°C) is 0.465 N m–1. The atmospheric pressure is 9 10 11 12 13 14 15
1.01 × 105 Pa. [310 N m-2]
A C C B A C A
THREE MARK QUESTIONS:
1. Derive an expression for gauge pressure inside a static fluid. ANSWERS TO FIBS:
2. Derive the equation of continuity. What is the significance of the equation?
1. surface tension; 2. viscosity; 3. turbulent; 4. dynamic lift; 5. hydraulic lift
3. Obtain the expression for the terminal velocity of a small sphere falling through a fluid.
4. Derive the expression for excess pressure inside a drop.
5. At a depth of 1000 m in an ocean (a) What is the absolute pressure? (b) What is the gauge pressure? (c)
***********************************************************************************
Find force acting on the window of area 20 cm × 20 cm of a submarine at this depth, the interior of
which is maintained at sea level atmospheric pressure. (Given: The Density of seawater is 1.03 × 103
kgm-3 and g = 10 ms-2) [(a) 104.01 × 105 Pa, (b) 103 × 105 Pa and (c) 4.12 × 105 N]
6. Two syringes of different cross-sections (without needles) filled with water are connected with a tightly
fitted rubber tube filled with water. Diameters of the smaller piston and larger piston are 1.0 cm and 3.0 10. THERMAL PROPERTIES OF MATTER
cm respectively. (a) Find the force exerted on the larger piston when a force of 10 N is applied to the
MULTIPLE CHOICE QUESTIONS:
smaller piston. (b) If the smaller piston is pushed in through 6.0 cm, how much does the larger piston
move out? [90 N, 0.67 cm] 1. Absolute zero (0 K) is that temperature at which
7. In a car-lift compressed air exerts a force F1 on a small piston having a radius of 5.0 cm. This pressure is (A) Matter ceases to exist (B) Ice melts and water freezes
transmitted to a second piston of radius 15 cm. If the mass of the car to be lifted is 1350 kg, calculate (C) Volume and pressure of a gas becomes zero (D) None of these
F1. What is the pressure necessary to accomplish this task? (g = 9.8 ms-2). [1.5 kN, 1.9 × 105 Pa] 2. The temperature at which same value of measurement in Celsius and Fahrenheit scale is
8. A metal block of area 0.10 m2 is connected to a 0.010 kg mass via a string (A) 00 (B) 1000 (C) 400 (D) - 400
that passes over an ideal pulley (considered massless and frictionless), as 3. Relation between coefficient of linear expansion(αL), coefficient of area expansion(αA) and
in figure. A liquid with a film thickness of 0.30 mm is placed between the coefficient of volume expansion(αV) is
block and the table. When released the block moves to the right with a (A) αL= αA and αV = αL (B) 2αL = αA and αV = 3 αL
constant speed of 0.085 m s-1. Find the coefficient of viscosity of the (C) αL= 2 αA and 3αV = αL (D) 3αL= αA and αV = 2αL
liquid. [3.46 × 10-3 Pa s]
4. 5 litre of benzene weighs 18. The variation of density of water with temperature is represented by the
(A) more in summer than in winter (B) more in winter than in summer
(C) equal in winter and summer (D) more in rainy season.

Density

Density
5. Water has maximum density at (A) (B)
(A) 00C (B) 320C (C) -40C (D) 40C
6. Water is used to cool radiators of engine because Temperature
Temperature
(A) of its lower density (B) it is easily available
(C) it is cheap (D)it has high specific heat.
(C) (D)

Density
7. At atmospheric pressure, the water boils at 1000C. if pressure is reduced, it will boil at

Density
(A) higher temperature (B) lower temperature
(C) at the same temperature (D) at critical temperature. Temperature
Temperature
8. For cooking the food which of the following type of utensil is most suitable
19. Which of the substances A, B or C has the highest specific heat ? The
(A) high specific heat and low conductivity. (B) high specific heat and high conductivity. X
temperature vs time graph is shown

Temperature (T)
(C) low specific heat and low conductivity. (D) low specific heat and high conductivity Y
(A) X (B) Y
9. Two thin blankets keep more hotness than one blanket of thickness equal to these two. The reason Z
(C) Z (D) all have equal specific heat
is
(A) Their surface area increases Time (t)
(B) A layer of air is formed between these two blankets, which is bad conductor
20. Shown below are the energy emitted by black body curves at temperatures T1 and T2 (T2>T1).
(C) These have more wool
Which of the following plots is correct
(D) They absorb more heat from outside.
(A) (B)
10. In order that the heat flows from one part of a solid to another part, what is required I
T2
T2
I
(A) Uniform density (B) Density gradient T1
T1
(C) Temperature gradient (D) Uniform temperature
11. The layers of atmosphere are heated through 

(A) conduction (B) convection (C) radiation (D) both (B) and (C)
(C) I
T2 (D)
12. The fastest mode of heat transfer is I T1
T1
(A) conduction (B) convection (C) radiation (D) both (A) and (C) T2
13. The temperature of stars determined by
(A) Stefan’s law (B) Wein’s displacement law 

(C) Kirchhoff’s law (D) Newton’s law.
14. The spectral energy distribution of star is maximum at twice temperature as that of sun. The total FILL IN THE BLANKS:
energy radiated by star is
(temperature, regelation, trade wind, calorimeter, sea breeze, sublimation)
(A) twice as that of the sun (B)same as that of the sun
1. __________ is the device used for measuring the quantity of heat.
(C) sixteen times as that of the sun (D) one sixteenth of sun.
2. The ____________ of the2solid during melting remains same.
15. Equal masses of two liquids are filled in two similar calorimeters. The rate of cooling will
3. The phenomenon in which refreezing of ice when pressure is removed is called ________.
(A) depend on the nature of the liquids
4. The process of change of state directly from solid to vapour is known as_________.
(B) depend on the specific heats of liquids
5. The steady wind blowing from North-East to equator, near the surface of earth is called __________.
(C) be same for both the liquids
(D) depend on the mass of the liquids. TWO MARK QUESTIONS:
16. In cold countries, water pipes sometimes burst, because 1. Write any two differences between heat and temperature.
(A) Water expands on freezing 2. What are two fixed points on a temperature scale?
(B) When water freezes, pressure increases 3. Draw a graph of Fahrenheit temperature versus Celsius temperature.
(C) pipes expand 4. State and explain Boyle’s law.
(D) when water freezes, it takes heat from pipes 5. State and explain Charle’s law at constant pressure.
17. A container contains hot water at 100 o C . If in time T1 temperature falls to 80 o C in time T2 6. Draw a graph of pressure versus temperature for low density gases indicates the same absolute zero
temperature falls to 60 o C
from 80 o C , then temperature.
(A) T1  T2 (B) T1  T2 (C) T1  T2 (D)None 7. Define co-efficient of linear expansion of a solid. Mention its SI unit.
8. Explain the meaning of the statement “the coefficient of linear expansion of silver is 0.000019 per FIVE MARK QUESTIONS:
kelvin. 1. State and explain the laws of thermal conductivity.
9. Define co-efficient of volume expansion of a solid. Write the expression for it. 2. Obtain the relation loge (T2 – T1) = Kt + C by using Newton’s law of cooling where the symbols have
10. What is meant by anomalous expansion of water? their usual meaning.
11. Explain the variation of volume of 1kg of water with temperature graphically. 3. A blacksmith fixes iron ring on the rim of wooden wheel of a bullock cart. The diameter of the rim and
12. At what temperature, the density of water is maximum? Mention the highest value of density of water. the iron ring are 5.243 m and 5.231 m respectively at 27 0C. To what temperature should the ring be
13. Name any two substances which neither expand nor contract on heating. heated so as to fit the rim of the wheel? Given α = 1.2 X10-5 K-1. [2180 C ]
14. Define heat capacity of a substance. Write its SI unit. 4. 0.2 kg of copper heated to 1000C is dropped into 0.1 kg of water at 300C contained in copper
15. Define specific heat capacity of a substance. Write its SI unit. calorimeter of mass 0.2 kg. If the specific heat of copper is 418 Jkg-1K-1 and that of water is 4200
16. Define (i) molar specific heat of a gas at constant volume and (ii) molar specific heat at constant Jkg-1K-1, find the maximum temperature attained by water. [400 C]
pressure. 5. A drilling machine of 5kW is used to drill a hole in the block of copper of mass 4.0kg. Calculate the rise
17. Cp is always greater than Cv. Why? in temperature of the block in 5 minutes if 75% of the energy is used in heating the block. Given
18. Mention the factors on which molar specific heats depend. specific heat of copper = 0.385 J g-1 0C-1. [730.520 C]
19. State and explain the principle of calorimetry. 6. A metal cylinder 0.628 m long and 0.04 m in diameter has one end in boiling water at 1000C and the
20. Define the terms (i) melting and (ii) fusion. other end in melting ice. The coefficient of thermal conductivity of the metal is 378 Wm-1K-1. Latent
21. Define the terms (i) vaporisation and (ii) sublimation. heat of ice is 3.36 × 105Jkg-1. Find the mass of ice that melts in one hour. [0.81 kg]
22. Define the terms (i) melting point and (ii) normal melting point. 7. A liquid takes 10 minutes to cool from 700 C to 500 C. How much time will it take to cool from 600 C to
23. What is regelation? Mention one of its practical applications. 400 C? The temperature of the surrounding is 200 C. [13.33 minutes]
24. Explain the possibility of ice skating.
25. Define the terms (i) boiling point and (ii) normal boiling point of a liquid. ANSWERS TO MULTIPLE CHOICE QUESTIONS:
26. Define latent heat of substance. Give its SI unit.
27. Define the terms (i) latent heat of fusion and (ii) latent heat of vapourisation. 1 2 3 4 5 6 7 8 9 10
28. Define coefficient of thermal conductivity. Mention its SI unit. C D B B D D B D B C
29. Why a metal bar does feel much colder than a wooden block on a cold day?
30. What are the values of thermal conductivity of a 11 12 13 14 15 16 17 18 19 20
(i) a perfect heat conductor and (ii) a perfect heat insulator. B C B C B A C A A A
31. Mention the types of convection.
32. Distinguish between conduction and convection. ANSWERS FOR FIBS:
33. State and explain Stefan-Boltzmann law of radiation.
34. State and explain Wein’s displacement law of radiation. 1. calorimeter 2. temperature 3. regelation 4. sublimation 5. trade wind
35. State and explain Newton’s law of cooling.
36. Convert 1000 F into degree Celsius scale. ***************************************************************************************

THREE MARK QUESTIONS:

1. Derive an ideal gas equation by using gas laws.
2. Write a note on absolute scale of temperature.
3. Mention the different types of thermal expansion. 11. THERMODYNAMICS
4. Derive αv = for an ideal gas, where the symbols have their usual meaning.
MULTIPLE CHOICE QUESTIONS
5. Show that αv = 3 αl, where the symbols have their usual meaning.
6. Mention three factors on which heat flow by conduction in a bar depends. 1. When two systems are in thermal equilibrium, the quantity which remains same in the two system
7. Mention any three properties of thermal radiation.
is
8. A metal bar measures 50 cm at 00C and 50.048 cm at 800C. Find the coefficient of linear expansion of
the metal. [1.2 × 10-5 /0C] (A) volume (B) pressure (C) temperature (D) density
9. Calculate the change in volume of an iron block 10 cm × 20 cm × 5 cm if its temperature is raised from 2. Temperature is a measurement of coldness or hotness of an object. This definition is based on
100C to 400C. Given coefficient of volume expansion of iron = 3.6 × 10-5 /0C. [1.08 cm3] (A) Zeroth law of thermodynamics (B) First law of thermodynamics
10. The two molar specific heats of a gas are 29.11J/mol/K. Calculate the universal gas constant. (C) Second law of thermodynamics (D) Newton's law of cooling
[8.32 J/mol/K] 3. The internal energy of an ideal gas depends on
11. The temperature of a furnace is 2500 K, find the heat radiated by it per second per square metre of its
-8 -2 -4 (A) specific volume (B) pressure (C) density (D) temperature
surface. Stefan’s constant = 5.7 × 10 Wm K . [ 2.23 × 106J]