Second year intermediate - Physics - Chapter 1

HEAT


DEFINITION

Total Kinetic energy of a body is known as HEAT.

OR

Transfer of energy from a hot body to a cold one is termed as Heat.
Heat is measured by using a measurement centimeter.


UNITS
Since heat is a force of energy therefore its unit is Joule (J).

TEMPERATURE:


DEFINITION

The average kinetic energy of a body is known as Temperature.

OR

The quantitative determination of degree of hotness may be termed as Temperature.


SCALES OF TEMPERATURE

There are three main scales of temperature.

  1. Celsius Scale

  2. Fahrenheit Scale

  3. Kelvin Scale

Celsius and Fahrenheit scales are also known as Scales of Graduation.


1. Celsius Scale

The melting point of ice and boiling point of water at standard pressure (76cm of Hg) taken to be two fixed points. On the Celsius (centigrade) scale the interval between these two fixed points is divided into hundred equal parts. Each part thus represents one degree Celsius (1°C). This scale was suggested by Celsius in 1742.
Mathematically,

°C = K - 273
OR
°C = 5/9 (°F - 32)


2. Fahrenheit Scale

The melting point of ice and boiling of water at standard pressure (76cm of Hg) are taken to be two fixed points. On Fahrenheit scale the lower fixed point is marked 32 and upper fixed point 212. The interval between them is equally divided into 180 parts. Each part represents one degree Fahrenheit (1°F).
Mathematically,

°F = 9/5 (°C + 32)


3. Kelvin Scale

The lowest temperature on Kelvin scale is -273°C. Thus 0° on Celsius scale will be 273 on Kelvin scale written as 273K and 100 on Celsius scale will be 373K. The size of Celsius and Kelvin scales are same.
Mathematically,

K = °C + 273



THERMAL EQUILIBRIUM


Heat flows from hot body to cold body till the temperature of the bodies becomes same, then they are said to be in Thermal Equilibrium.

THERMAL EXPANSION


DEFINITION

The phenomenon due to which solid experience a change in its length, volume or area on heating is known as Thermal Expansion.


Explanation

If we supply some amount of heat to any substance then size or shape of the substance will increase. This increment is known as Thermal Expansion. Thermal expansion is due to the increment of the amplitudes of the molecules.


Types of Thermal Expansion
There are three types of Thermal Expansion.

  1. Linear Expansion

  2. Superficial Expansion

  3. Volumetric Expansion.


1. Linear Expansion.
If we supply some amount of heat to any rod, then the length of the rod, then the length of the rod will increase. Such increment is known as Linear Expansion.


2. Superficial Expansion.
If we apply some amount of heat to any square or rectangle then area of the square or rectangle will increase. Such increment is known as Superficial Expansion.


3. Volumetric Expansion.
If we apply some amount of heat to any cube, then the volume of the cube will increase. Such increment is known as Volumetric Expansion.


COEFFICIENT OF LINEAR EXPANSION


CONSIDERATION
Let Lo be the initial length of rod at t1 °C. If we increase the temperature from t1 °C to t2 °C, then length of the rod will increase. This increment in length is denoted by ΔL. The increment in length depends upon the following two factors.
1. Original Length (Lo)
2. Difference in temperature Δt


Derivation
The increment in length is directly proportional to the original length and temperature difference.
Mathematically,
                           ΔL ∞ Lo ----- (I)
                           ΔL ∞ Δt ----- (II)

               Combining eq (I) and (II), we get

                           ΔL ∞ LoΔt
                     => ΔL = ∞LoΔt


Where α is the constant of proportionality and it is known as coefficient of Linear Expansion. It is defined as,

It is the increment in length per unit length per degree rise in temperature.

Its unit is 1/°C or °C. If Lt is the total length, then

                        Lt = Lo + ΔL
                   => Lt = Lo + αLoΔt
                   => Lt = Lo (1 + αΔt)

COEFFICIENT OF VOLUMETRIC EXPANSION


Consideration
Let Vo be the initial length of rod at t1 °C. If we increase the temperature from t1°C to t2°C then length of the rod will increase. This increment in length is denoted by ΔV. The increment in length depends upon the following two factors.
3. Original Volume (Lo)
4. Difference in temperature Δt


Derivation
The increment in volume is directly proportional to the original volume of temperature difference.
Mathematically,

                          ΔV ∞ Vo ---- (I)
                          ΔV ∞ Δt ---- (II)

               Combining eq (I) and (II), we get,
                        
                         ΔV ∞ Vo Δt
                    => ΔV = βVoΔt

Where β is the constant of proportionality and it is known as coefficient of Volumetric Expansion. It is defined as

It is the increment in volume per unit volume per degree rise in temperature.

Its unit is 1/°C or °C-1. If Vt is the total volume then

                        Vt = Vo + ΔV
                  => Vt = Vo + αβVo Δt
                  => Vt = Vo (1 + βΔt)


State and Explain Boyle's Law and Charle's Law.


INTRODUCTION

Gas Laws are the laws, which give relationship between Pressure, Volume, temperature and mass of the gas. There are two gas laws.


1. Boyle's Law

2. Charle's Law


BOYLE'S LAW


Statement 1
According to first statement of Boyle's Law:

Volume of the known mass of gas is inversely proportional to the pressure, if temperature is kept constant.

Mathematical Form

Mathematically,

                         V ∞ 1/P
                    => V = K 1/P
                  => PV = K (Constant)
                       P1V1 = P2V2 = ... = K
                  => P1V1 = P2V2

The above equation is mathematical form of Boyle's Law.

Statement II
According to second statement of Boyle's Law.

The product of the pressure and volume of the known mass of the gas remain constant if the temperature is kept constant.


Statement III
According to third statement of Boyle's Law.

The product of pressure and volume of a gas is directly proportional to the mass of a gas, provided that temperature is kept constant.


Mathematical Form

Mathematically,
                             PV ∞ m
                       => PV = Km 
                       => PV/m = K
                       => P1V1/m1 = P2V2/m2


Limitations of Boyle's Law

Boyle's Law does not hold good at high pressure, because at high pressure gases convert into liquid or solid.


Graphical Representation

The graph between pressure and volume is a curved line, which shows that volume and pressure are inversely proportional to each other.



CHARLE'S LAW


Statement I
According to first statement of Charle's Law.

Volume of known mass of gas is directly proportional to the absolute temperature, if then pressure is kept constant.

Mathematical Form

Mathematically,
                            V ∞ T
                      => V = KT
                      => V/T = K

                              OR

                      => V1/T1 = V2/T2


The above equation is mathematical form of Charles Law.


Statement II
According to second statement of Charles Law.

The ratio between volume and temperature of the known mass of a gas is always constant, if pressure is kept constant.


Limitations of the Law

This law does not hold good at low temperature because at low temperature gases convert into liquid or solid.


GENERAL GAS EQUATION


It is the combination of Boyle's law, Charle's Law and Avogadro's Law. According to Boyle's Law.
V ∞ 1/P ---- (I)
According to Charle's Law
V ∞ T ---- (II)
According to Avogadro's Law
V ∞ n ---- (III)
Combining eq (I), eq (II) and eq (III)
V α nT/P
=> V = RnT/P
            => PV = RnT ---- (A)
Where R is the universal gas constant, We Know that
R = R/NA
=> R = KNA
Where K is the Boltzman constant, Its value is
K = 1.38 x 10(-23) J/K

Substituting the value of R in eq (A)
=> PV = nKNAT
=> PV = nNAKT
But nNA = N1 (Total number of molecules), therefore,
PV = NtKT
=> P = Nt/V KT
Since Nt/V = N (Total Number of molecules in a given volume), therefore,
P = NKT
The above equation is other form of General Gas Equation.



What are the basic postulates of Kinetic Molecular Theory pf Gases?


INTRODUCTION
The properties of matter in bulk can however be predicted on molecular basis by a theory known as Kinetic Molecular theory of gases. The characteristic of this theory are described by some fundamental assumptions, which explained below:


BASIC POSTULATES OF KINETIC MOLECULAR THEORY OF GASES


1. Composition
All gases are composed of small, spherical solid particle called molecules.

2. Dimension of Molecules
The dimensions of the molecules is compared to the separation between the molecule is very small.

3. Number of Molecules
At standard condition, there are 3 x 10(23) molecules in a cubic meter.

4. Pressure of Gas
Gas molecules collide with each other as well as with the wall of the container and exert force on the walls of the container. This force per unit are is known as Pressure.

5. Collision Between the Molecules
The collision between the molecules is elastic in which momentum and Kinetic energy remains constant.

7. Kinetic Energy of Molecules
If we increase the temperature of gas molecules, then K.E will also increase. It means that average kinetic energy of the gas molecules is directly proportional to the absolute temperature.

8. Forces of Interaction
There is no force of attraction or repulsion between the molecules.

9. Law of Mechanics
Newtonian mechanics is applicable to the motion of molecules.


THERMODYNAMICS


DEFINITIONS:

The branch of Physics that deals with the conversion of heat energy into mechanical energy or work or transformation of work into heat energy is known as Thermodynamics.


Laws of Thermodynamics
There are two laws of thermodynamics.
1. First Law of Thermodynamics
2. Second Law of Thermodynamics


State and explain first law of Thermodynamics. What are the applications of first law of Thermodynamics?

FIRST LAW OF THERMODYNAMICS


First Statement
Whenever heat energy is converted into work or work is transformed into heat energy, the total amount of heat energy is directly proportional to the total amount of work done.

Mathematical Expression

Mathematically,
                              Q ∞ W
                         => Q = JW

Where J is the mechanical equivalent of heat or joules constant. Its value is 4.2 joules.


Second Statement
If ΔQ is the amount of heat supplied to any system, then this heat will be utilized to increase the internal energy of the system in the work done in order to move the piston.

Mathematical Expression

Mathematically,
                            ΔQ - Au + Δw
The above equation is the mathematical form of first law of thermodynamics.
Where

Δu = Internal energy of the system.
Δw = Amount of work done.
ΔQ will be positive when heat is supplied to the system and it is negative when heat is rejected by the system.
Δw will be positive when work is done by the system and it will be negative when work is done on the system.


Third Statement
For a cyclic process, the heat energy supplied to a system and work done on the system is equal to the sum of heat energy rejected by the system.

Mathematical Expression

Mathematically,
                            Q(IN) + W(IN) = Q(OUT) + W(OUT)
                            Q(IN) - Q(OUT) = W(OUT) + W(IN)
                          ΔQ = ΔW
                         {dQ = {dW
                         {Shows cyclic process


Fourth Statement
For a system and surrounding the total amount of heat energy remains constant


APPLICATIONS OF THE LAW
There are four applications of first law of Thermodynamics.
1. Isometric or Isochoric Process.
2. Isobaric Process
3. Isothermal Process
4. Adiabatic Process



1. Isometric or Isochoric Process
The process in which volume of the system remains constant is known as Isometric Process.
In this process all supplied amount of heat is utilized to increase the internal energy of the system.

Mathematical Form
In this process first law of thermodynamics take the following form.
                                   ΔQ = Δu + ΔW
                          But,
                                  ΔW = 0
                             => ΔQ = Δu = 0
                             => ΔQ = Δu



2. Isobaric Process
The process in which pressure is kept constant is known as isobaric process.
In this process, all supplied amount of heat is utilized for the following two functions.
i. To increase the internal energy of the system.
ii. In work done in order to move the piston upward.



3. Isothermal Process
A process in which temperature is kept constant is known as Isothermal Process.
There are two parts of isothermal process.
i. Isothermal Expansion
ii. Isothermal Compression



i. Isothermal Expansion
In this process cylinder is placed on a source and piston is allowed to move upward. When we do so temperature and pressure of the working substance will decrease while volume will increase. In order to keep the temperature constant, we have to supply required amount of heat from source to cylinder.
Since in this expansion, temperature is constant therefore it is known as Isothermal Expansion.



ii. Isothermal Compression
In this process, cylinder is placed on a sink and piston is allowed to move downward. When we do so temperature and pressure of working substance will increase while volume will decrease. In order to maintain the temperature, we have to reject required amount of heat from cylinder to the sink.
Since in this compression, temperature is kept constant therefore it is known as isothermal compression.


SECOND LAW OF THERMODYNAMICS

Introduction
It is inherit tendency of heat that it always flows from hot reservoir to cold reservoir. Rather than to flow in both the directions with equal probability. On the basis of this tendency of heat a law was proposed that is known as Second Law of Thermodynamics.


Statement
It is impossible to construct a process which reserves the natural tendency of heat.
This law is also known as Law of heat and can also be stated as
Efficiency of heat engine is always less than unity.


Explanation
Many statements of this law has been proposed to cover similar but different point of vies in which two are given below.
1. Lord Kelvin Statement
2. Clausius Statement


1. Lord Kelvin Statement
According to this statement,
It is impossible to construct a heat engine which extract all heat form the source and convert it into equal amount of work done and no heat is given to the sink.

Mathematically,
                               Q1 ≠ W
                               Q2 ≠ O


2. Clausius Statement
According to Clausius Statement,
Without the performance of external work heat cannot flow from cold reservoir towards, the hot reservoir.


Example
In case of refrigerator flow of heat is unnatural but this unnatural flow of heat is possible only when we apply electrical power on the pump of the refrigerator.


Define the term Entropy and Give its Uses

ENTROPY


Definition
It measures the disorderness of any system.

Mathematically,
ΔS = ΔQ/T
Where Δs shows change in entropy.

Units
Joule per degree Kelvin - J/°K.


Explanation
As we know that incase of isometric process volume is constant. In case of Isothermal process temperature and pressure is constant, but in case of adiabatic process neither temperature, nor pressure or volume is constant but one thermal property is constant which is known as Entropy.
There are two types of Entropy.
1. Positive Entropy
2. Negative Entropy


1. Positive Entropy
If heat is supplied to the system the entropy will be positive.


2. Negative Entropy
When heat is rejected by the system the entropy will be negative.


What is Carnot engine an Carnot cycle?


CARNOT ENGINE


Definition
'Carnot engine is an ideal heat engine which converts heat energy into mechanical energy.


Working of Carnot Engine
It consists of a cylinder and a piston. The walls of the cylinder are non-conducting while the bottom surface is the conducting one. The piston is also non-conducting and friction less. It works in four steps. Which are as follows.
1. Isothermal Expansion
2. Adiabatic Expansion
3. Isothermal Compression
4. Adiabatic Compression


1. Isothermal Expansion
First of all, cylinder is placed on a source and allow to move upward as a result temperature and pressure of the working substance decreases, while volume increases. In order to maintain temperature we have to supply more amount of heat from source to the cylinder. Since in this expansion temperature is kept constant.


2. Adiabatic Expansion
Secondly cylinder is placed on an insulator and piston is allowed to move downward as a result temperature and pressure of working substance will decrease. While volume will increase but no heat is given or taken of the cylinder.


3. Isothermal Compression
In this state cylinder is placed on a sink and piston is allow to move downward as a result temperature and pressure of the working substance will increase while volume will decrease. In order to maintain temperature we have to reject extra heat from cylinder to the sink. Since in this compression temperature is constant.


4. Adiabatic Compression
Finally cylinder is placed on an insulator and piston is a flow to move downward, when we do so neither temperature nor pressure or volume is constant. But no heat is given or taken out of the cylinder.


CARNOT CYCLE

By combining the four processes Isothermal Expansion, Adiabatic Expansion, Isothermal Compression and Adiabatic Compression which are carried out in Carnot engine, then we get a cycle knows as Carnot cycle.


How can we increase the efficiency of Heat Engine?

If we want to increase the efficiency of any heat engine then for this purpose we have to increase temperature of source as maximum as possible and reduce the temperature of sink as minimum as possible.


Define Specific Heat and Molar Specific Heat.

SPECIFIC HEAT


Definition
Specific heat is the amount of heat required to raise the temperature of a unit mass of a substance by one degree centigrade.
Different substances have different specific heat because number of molecules in one kg is different in different substances. It is denoted by c.

Mathematical Expression

Consider a substance having mass m at the temperature t1. The amount of heat supplied is ΔQ, which raises the temperature to t2. The change in temperature is Δt.
The quantity of heat is directly proportional to the mass of the substance.
                                       ΔQ ∞ m
And the temperature difference
                                       ΔQ ∞ Δt
Combining both the equations
                                       ΔQ ∞ mΔt
                                  => ΔQ = cmΔt
                            => c = ΔQ / mΔt ---- (I)
Where c is the specific heat of the substance. Its unit is Joules / Kg°C.

MOLAR SPECIFIC HEAT


Definition
Molar specific heat is the amount of heat required to raise the temperature of one mole of a substance through one degree Celsius.
Almost all the substances have the same amount of molar specific heat because the numbers of molecules in all substances are same in one mole. It is denoted by cM.


Mathematical Expression

Mathematically,
No. of Moles = Mass / Molecular Mass
=> n = m / M
=> nM = m
=> nM = ΔQ / nΔt
Where n is the number of moles. The unit of molar specific heat is J/Kg°C.


Define Molar Specific Heat at Constant volume and at Constant Pressure.

MOLAR SPECIFIC HEAT AT CONSTANT VOLUME


Definitions
The amount of heat required to raise the temperature of one mole of any gas through one degree centigrade, at constant volume is known as molar specific heat volume.
It is denoted by Cv.


Mathematical Expression
Mathematically,
ΔQv = nCvΔt
Where ΔQv is the heat supplied at constant volume.

MOLAR SPECIFIC HEAT AT CONSTANT PRESSURE


Definition
The amount of heat required to raise the temperature of unit mass of a substance through one degree centigrade at constant pressure is known as Molar Specific Heat at Constant Pressure.
It is denoted by Cp.

Mathematical Expression
Mathematically,
ΔQp = nCpΔt
Where ΔQp is the heat supplied at constant volume.

Second year intermediate - English - Grammer

Grammar


Idioms & Phrases


1. At sixes and sevens: Home ruler, who were all at sixes and sevens among themselves agreed only upon the one thing and that was the freedom of India.
2. All in all: The Head clerk is all in all in this office.
3. All the same: It is all the same to me whether the pull over is home-made or bazaar-made.
4. At large: The culprits are still at large.
5. By fits and starts: He works by fits and starts and does not apply him steadily.
6. Black sheep: We should be aware of the black sheep in our society.
7. A bone of contention: This property is a bone of contention between the two brothers.
8. To break the ice: We all wanted to talk on this subject by no one willing to break the ice.
9. A burning question: Kashmir is a burning question of the day.
10. To back out: He promised to help me but backed out at the eleventh hour.
11. To beat about the bush: Stop beating about the bush; say exactly what you mean.
12. Bed of roses: A military life is not bed of roses.
13. In cold blood: He murdered the merchant in cold blood.
14. To fall to the ground: The theory has fallen to the ground.
15. Go hand in hand: Diligence and prosperity go hand in hand.
16. Leave no stone unturned: Shah Faisal left no stone unturned to bring about unity in the Islamic world.
17. Live from hand to mouth: Our middle class people live generally from hand to mouth.
18. Look down upon: He is so proud of his promotion that he looks down upon all his former friends.
19. At a loss: He is never at a loss for an appropriate word.
20. To pay back in the same coin: If a person rude towards you, it does not mean that you should pay him in the same coin.
21. To keep pace with: Agriculture in the states has kept pace with manufacture, but it has far out stepped commerce.
22. Red tape: Flourence Nightingale was a sworn enemy of red tape.
23. To speak volumes: The murders spoke volumes about political conditions before Indian elections.
24. Up to the mark: You don’t look quite up to the mark today.
25. To get into hot water: Do not quarrel with your officers or you will soon get into hot water.
26. Time and again: Time and again proverbs come to be true.
27. Cut off: The supplies were cut off from the soldier due to snow fall.
28. Run against: Zuhair Akram Nadeem was running against Dr. Farooq Sattar in the elections 89.
29. To turn over a new leaf: The teacher pardoned the boy on the condition that he promised to turn over a new leaf in future.
30. To nip in the bud: The plot to overthrow the Government was detected and nipped in the bud.
31. To feel like a fish out of water: Being the only educated person in that village, I felt like a fish out of water.
32. To shed crocodile tears: Don’t be deceived by the beggar’s crying. They are only crocodile’s tears.
33. Lion share: The stronger person generally gets the lions share of the property.
34. To cry over spilt milk: The damage has been done but instead of crying over spilt milk do something to repair it.
35. It is high time: The exams begin next month so it is high time to study seriously.
36. To save something for the rainy day: He wasted his savings and has kept nothing for the rainy day.
37. With a high hand: He is the most unpopular because he decides matters with a high hand.
38. Day in and day out: I have been warning you day in and day out.
39. To make the most of: He let me use his bicycle for a week and I am going to make the most of it.
40. To make the fun of: We should not make fun of handicaps.
41. To make room for: They made room for more guests as all seats were full.
42. To go through: He went through the whole book within a week.
43. In all: He got 782 marks in all.
44. All alone: Yesterday night she was all alone in her house.
45. To put into practice: The Holy Prophet (P.B.U.H) put into practice what he preaches.
46. A wild goose chase: The robbers fled away and the police gave them a wild goose chase.
47. To end in smoke: All his efforts ended in smoke because they were not made sincerely.
48. With flying colors: If you work hard you will pass your examination with flying colors.
49. Odds and ends: The shopkeeper does not sell any particular article, but deals in odds and ends.
50. Under one’s nose: The police were on the look out for the culprit who was hiding under their nose.
51. To poke one’s nose into: One should not poke one’s nose into others affairs.
52. To kick up a row: It is useless kicking up a row when the matters can be decided peacefully.
53. To wind up: He is winding up his business in the city, as he going abroad.
54. In black and white: I want your statement in black and white.
55. A red letter day: 14th August is a red letter day in the history of Pakistan.
56. To run into: Last night my friend ran into a cheat who deprived him of his brief case by changing it with an empty one.
57. To bring to light: A number of facts were brought to light by the Prime Minister in the recent Press Conference.
58. At the eleventh hour: The president postponed his meeting with the journalists due to visit of the French delegation at the eleventh hour.
59. To come across: In the wedding party, she comes across he two very close friends of the University life.
60. To give up: The doctor has strictly advised him to give up drinking and smoking for the sake of his life.
61. To call a spade, a spade: Islam teaches us to call a spade, a spade even before a cruel ruler.
62. To look after: All the parents have to look after their children during the early period of the school life.
63. To break up: The two partners have decided to break up the partnership and divide the assets equally.
64. To get rid of: Pakistan must get rid of that type of foreign aid, which puts on her, undue political pressure.
65. At a stretch: Saeed Anwar played an aggressive inning and continued to score runs at a stretch.
66. To give in: Imran Khan and Miandad were real fighters and they would never give in till the last ball.
67. To let down: The rich feel proud of their wealth and usually let down the poor.
68. Once in a blue moon: I am not so fond of movies and watch some fine art movie once in a blue moon.
69. To fall out: A short tempered football player fell out with his opponents and got wounded.
70. To call on: The winners of 1994 World Cup called on the President, with their captain.
71. To call off: The University students finally decided to call off the strike as their demands were accepted.
72. To bring home to: Rizwan brought home to her all the important aspects of the matter.
73. To get over: The Indian Government made all possible efforts to get over the epidemic of plague.
74. To get across: The news of Mr. Edhi’s self-exile got across the country within no time.
75. To make up for: The Government and people of Iraq are working day and night to make up the loss caused by the Gulf war.
76. To make off: The robbers made off through the back door just as the security guard started firing into air.
77. To bring out: The telephone Corporation has brought a decent Directory in three volumes.
78. To bring up: Abraham Lincoln was brought up by his parents in a state of very limited financial resources.
79. To take off: The Hajj flight will take off every morning during the next couple of weeks.
80. To take place: The wedding of my cousin will take place in the first week of November, next.
81. To keep up: Our cricket team must go through an extensive training and practice session to keep up their position in the next world cup.
82. To stir up: The statement given by Mr. Abdul Sattar Edhi caused great stir up in the political circles.
83. To go off: While the police man was cleaning his rifle, it suddenly went off because it was loaded.
84. To let off: Finally, the defaulter was let off by the civil authorities in view of his undertaking to abide by the rules in future.
85. To beg for: The Quaid-e-Azam begged for peace and friendship with his former enemies, the Congress leaders.
86. To furnish with: The chief justice was furnished with all the documentary proofs against the accused.
87. To look for: After the panic had subsided, people started looking for their misplaced baggage.
88. To run after: According to Einstein, ordinary people run after ordinary objects such as property and luxury.
89. To turn down: The secretary was taking down the main points to prepare a summary of the Seminar on pollution.
90. To watch over: Sensible parents make it a point to watch over the outdoor activities of their growing up children.
91. To bank on: Never bank on a fair weather friend because he will certainly cheat you.
92. To blow hot and cold: It is part of his nature to blow hot and cold as he favours this political party today the other party tomorrow.
93. To break the news: It was really very hard to break the shocking news of her husband’s accidental death to her.
94. To call names: He is such loose tempered man that he often begins to call names to his neighbors.
95. To turn the tables: The pace attack by Wasim Akram and Waqar turned the tables against India and our cricket team got victory.
96. To hold water: The judge will give a favourable verdict only when you lawyer’s arguments hold water.
97. To face the music: Those who are responsible for terrorism in the city must face the music and be dealt with.
98. To be under the cloud: These days, the opposition leaders are under a cloud and being tortured by the Government.
99. By hook or by crook: The corrupt politicians try to win in every general election by hook or by crook.
100. To run short of: These days most areas in Karachi are running short of water supply.



Direct and Indirect Speech


Direct Speech

Direct speech is that form of narration in which the actual words of a speaker are reported. It may be divided into two parts: the reported speech, i.e. the actual words of the speaker; and the reporting speech, i.e., the introductory words added to the reported speech. The reported speech comes before or after commas.

Indirect Speech

Indirect speech is that form of speech in which what one speaker says is reported by another with utmost accuracy but without using his actual words.

Rules

For correct transcription from direct speech to indirect speech, the following rules should be carefully studied.

1. Elimination of Inverted Commas

i. In the indirect speech the commas are omitted
ii. The conjunction that, except in certain cases which will be discussed later, is used to join the reporting speech and the reported speech.
iii. The capital letter of the first word of the reported speech is replaced by a small letter.
Najma says, “The fat dog is barking.” Where (Najma says) is a reporting speech and (The fat dog is barking) is a reported speech.
In the indirect speech this sentence will read as:
Najma says that the fat dog is barking.

2. Change of Pronouns

The pronouns in the reported speech are to be changed when necessary.
i. Pronouns of the first person are changed to the person of the subject of the reporting speech. For example: He (subject of reporting speech) says, “I have (pronoun of first person) no money with me (pronoun of first person).”
As the subject of the reporting speech is in the third person, the pronouns of the first person will change accordingly. The sentence will read:
He says that he has no money with him.
ii. Pronouns of the second person are changed to the person of the noun/pronoun to whom the reported speech is addressed. For example:
You said to Zain, “I would be happy to welcome you in my house.”
The pronoun of the second person in the reported speech is you. It is to be changed to the object of the reported speech, which is Zain, i.e. third person. The sentence will read as:
You told Zain that you would be happy to welcome him in you house.

3. Change of Tense

i. If the verb of the reporting speech is in the present or future tense, the tense of the verbs of the reported speech does not change.
Direct: He says, “I am a poor but honest man, and will not pick anybody’s pocket.”
Indirect: He says that he is a poor but honest man, and will not pick anybody’s pocket.
ii. If the verb of the reporting speech is in the past tense the verbs of the reported speech are changed to past tense:
Present Indefinite to Past Indefinite
Present Continuous to Past Continuous
Present Perfect to Past Perfect
Present Perfect Continuous to Past Perfect Continuous
Past Indefinite to Past Perfect/Past Indefinite
Will/shall to would/should
Can/may to could/might
Note: If the reported speech expresses a universal truth, its tense will not change.

4. Question

i. When a question with why, what, how etc., is to be changed into indirect speech, the verb of the reporting speech is replaced by inquired, demanded or asked and the conjunction that is not used. The question changes into a statement.
Direct: I said to him, “What is you next plan?”
Indirect: I asked him what his next plan was.
Direct: He said to the little boy, “Why are you weeping?”
Indirect: He inquired of the little boy why he was weeping.
ii. When questions beginning with an auxiliary verb are to be changed into indirect speech, if or whether is used to join the reporting speech and the reported speech, and the question is converted into a statement.
Direct: He said to the teacher. “Do you think my essay is good?”
Indirect: He asked the teacher if the though his essay was good.

5. Commands and Requests

In direct speech, commands and requests are introduced with an infinitive and the reporting verb is replaced by told, ordered commanded, requested, etc., according to the sense of the sentence.
Direct: He said to his servant, “Fetch me a glass of water.”
Indirect: He ordered his servant to fetch him a glass of water.”
Direct: I said to him, “Please sit down.”
Indirect: I requested him to sit down.

6. Desires and Exclamations

When desires and exclamations are changed into indirect speech, the reporting verb is replaced by wished, desired, exclaimed, cried, etc., and that is used as conjunction to join the reporting speech and the reported speech.
Direct: He said, “Alas! I have done what cannot be undone.”
Indirect: He exclaimed with sorrow that he had done what could not be undone.

7. Change o Demonstrative Pronouns and Adjectives

The words showing nearness in time and space are changed to words showing distance unless the sense requires otherwise.
Direct: He said, “I wandered here and there.”
Indirect: We cannot replace here by there.
Direct Speech      Indirect Speech     Direct Speech     Indirect Speech

It                        That                 Now                Then
 
Ago                  Before              This                That 
 
Here                 There                Thus               So
 
These               Those                Hence            Thence
 
Today             That day           Tonight          That night
 
Last night      The previous night         Tomorrow          The next day
 
Yesterday     The previous day             The next day      The following day


Practice Exercise

1. “It is certainly a great privilege to hear you talk,” answered little Hans sitting down and wiping his forehead, “A very great privilege. But I am afraid I shall never have such beautiful ideas as you have.”

2. “What a silly boy you are!” cried the miller. “I really don’t know what is the use of sending you to school. You seem not to learn anything. If little Hans come here and saw our warm fire and our good super, and our great cask of wine, he might get envious, and envy is the most terrible thing and would spoil anybody’s nature.

3. “Sir, you hand better let me take you hose to the blacksmith to have a shoe put on.” “No,” said the farmer, “It does not matter much. I am already late and if I wait I will get still more lately. I have only a few miles to go and my horse can take me so far without a shoe.”

4. The teacher became angry with the student and said, “Why have you disturbed the class in this way? I have told you before that when I am speaking you should be silent. Leave the room and do not return today."

5. She said to the king, “Has your Majesty any doubt of this man’s guilt? There is the very sword with which he meant to kill you. How sharp and bright and terrible it is! Quick, let him taste the milk; or he may perhaps do the deed even yet.”

6. “Sir, I want work. May I earn a penny?” said the lad, “Well,” said the man, after a pause, “you shall take my son home, and I will give you a penny. Shall I give you your penny now?”

7. “What do you want to know?” the Owl asked. “I am seeking the wild goose.” Replied the little Boy. The Owl blinked, coughed a little and said, “The wild goose is an inhabitant of many parts of the globe. It fled westward half an hour before sunset.”

8. “Do you come to make inquiries?” he said. “I do,” the young stranger replied. “A friend of mine is missing and I think he is staying with you.” “Yes, I have a man staying with me, but I do not know whether he is your missing friend,” he said.

9. “You are very ill-mannered Giant,” answered the stranger quietly, “and I shall probably have to teach you a little civility before we part. As for my name, it is Hercules. I have come hither because this is my most convenient road to the garden of Hesperides whither I am going to get three of the golden apples for the King Eurystheus.”

10. “I have begun my picture of yours among the Scotch firs, Maggie,” said Philip, “so you must let me study your face. Please turn you head this way.” “I shall be sitting for my second portrait then,” she said smiling. “Will it be larger than the other?” “Oh yes, much larger. It is an oil painting, “replied Philip.

11. “What in the world, my little fellow,” said Hercules, “may you be?” “I am your enemy,” answered the valiant pygmy, “You have slain the enormous Antae us, our brother, and for ages the faithful ally of our nation. We are determined to put you to death. I challenge you to instant battle on equal ground.”

12. “I seem to myself like a child,” said Newton, “playing on the sea shore and picking up here and there a curious shell or a pretty pebble, while the boundless ocean of Truth lies undiscovered before me.”

13. “Mother,” he said, “Whatever you do, you will always be dear to me. But one thing I have a right to say, which is, that at my age I am old enough to know what is best for me.”

14. Peterkin said gravely, “Do you believe in ghosts, Ralph?” “No,” Ralph answered, “I do not. Nevertheless, I must confess that strange unaccountable sounds, such as we have just heard, make me feel a little uneasy.”

15. “They got the money, you say? Hawkins, what were they after? More money. I suppose?” he said, “No sir, not money I think,” replied Hawkins, “In fact, sir, I believe I have the thing in my breast-pocket. To tell you the truth, I should like to get it put in safety.”