THE PUNJAB PUBLIC SCHOOL, NABHA

SUMMER HOLIDAYS HOMEWORK-2020

UPCOMING CLASS VIII (SESSION 2020-2021)

SUBJECT- ENGLISH

Write a composition of 300 words on the following topics:

a. Some events or incidents change everything and force us to learn new

lessons. Reflect on the present times and write about the lessons learnt

during the times of Coronavirus spread in the world.

b. Describe your feelings about having to stay at home during these

holidays.

Watch any five English movies on the TV and write about the following:

a. The character you liked the most.

b. The most interesting event in the movie.

c. Describe the plot of the movie.

Revise tenses, reported speech and active-passive voice.

Look up thirty new words and write their meanings.

Use a new word in your conversation every day.

Read two story books of your choice.

SUBJECT- PHYSICS

1) Go through the power point presentation thoroughly and solve the questions given

below.

IntrotoEnergyPowerpointKineticPotentialwithembeddedcontent.pptx

PotentialandKineticEnergy.docx

2) Research on the topic REFRACTION OF LIGHT THROUGH PLANE AND

SPHERICAL SURFACES and do written practice of Ray Diagrams of Refraction through

lenses.

3) Go through the power point presentation thoroughly and solve the assignment followed:

PhysicalScience161SoundandLight.pptx

EnergyLightandSoundExam.docx

SUBJECT: CHEMISTRY

Introduction : Chemistry is the branch of science concerned with the substances of which

matter is composed, the investigation of the properties and reactions and the use of such

reactions to form new substances.

The language of chemistry includes the symbol of elements , molecular formula ,

valencies of an elements, molecular masses and others basics terms of chemistry.

Topic (A)

Symbol: It is defined as the short hand notation of an elements or abbreviations used to refer

the names of elements. For example Hydrogen (H) Sodium (Na) symbol of cobalt is Co not CO.

Significance of symbol:

(a) It represent a specific element.

(b) It represent one atom of an element

(c) It represent number of times of amn atom is heavier than one atomic mass unit taken as

standards.

Topic (B)

Atomicity: A set of atoms together to form molecules of element or the number of atoms in

molecules is called atomicity (OR) It is defined as the total number of atoms that constitute

a molecule. For example, each molecule of oxygen (O2) is composed of two oxygen atoms. So

atomicity of oxygen is 2. In older contexts, the term atomicity is sometimes used in the same

sense as valency.

On the basis of atomicity, molecules can be classified as :

Monoatomic-composed of 1 atom e.g. He, Ne, Ar (all noble gases are monoatomic)

Diiatomic composed of 2 atoms e.g. H2 , N2 , O2

Triatomic composed of 3 atoms e.g. O3

Polyatomic-composed of 3 or more atoms e.g. P4 , S8

All metals and some other elements, such as carbon do not have a simple structure but consist of a very large and indefinite number of atoms bonded together. Their atomicity cannot be determined and is usually considered as 1

Atomicity Of First 20 Elements

Atomic Number Element Atomicity

1 Hydrogen 2

2 Helium 1

3 Lithium 1

4 Beryllium 1

5 Boron 1*

6 Carbon 1

7 Nitogen 2

8 Oxygen 2

9 Fluorine 2

10 Neon 1

11 Sodium 1

12 Magnesium 1

13 Aluminium 1

14 Silicon 1**

15 Phosphorous 4

16 Sulfur 8

17 Chlorine 2

18 Argon 1

19 Pottasium 1

20 Calcium 2

CHEMISTRY…. Continue

Multiple Choice questions

Q. H is the chemical symbol for which element?

Helium Hydrogen

Mercury

Q. Na is the chemical symbol for which element?

Sodium Nitrogen

Neon

Q. K is the chemical symbol for which element?

Krypton Potassium

Knox

Q. Ca is the chemical symbol for which element?

Carbon Chlorine

Calcium

Q. Fe is the chemical symbol for which element?

Freon Iron

Flourine

Q. C is the chemical symbol for which element?

Calcium Chlorine

Carbon

Q. N is the chemical symbol for which element?

Sodium Nitrogen

Nickel

Q. O is the chemical symbol for which element?

Osmium Odell

Oxygen

Q. Si is the chemical symbol for which element?

CHEMISTRY…. Continue

Silicon Sodium

Sulfur

Q. He is the chemical symbol for which element?

Heehaw Helfion

Helium

Fill in the blanks

(a) Dalton used symbol ……………for oxygen and ……………..for hydrogen.

(b) Valency of hydrogen is …………………..and oxygen is ………………

(c) Symbolic expression for molecules is called………….

(d) Noble gases are ……………..atomic.

Topic (C)

Radicals: The radicals are the atoms and group of atoms having positive and negative charges. These are of two types

Acidic Radicals : These are negatively charged species. Basic Radicals : These are Positively charged species.

Examples of radicals are Na+ Cl- SO42- NO3

-

CHEMISTRY…. Continue

Complete the following table.

Acid Radicals

Basic Radicals

Chloride Cl-

Nitrate (NO3

-) Sulphate SO4

2- Carbonate CO3

2- Hydroxide OH-

Phosphate PO4

3-

Magnesium Mg2+

MgCl2 Mg(NO3)2 MgSO4 MgCO3 Mg(OH)2 Mg3(PO4)2

Sodium Na+

Zinc Zn2+

Silver Ag+

Ammonium NH4

+

Calcium Ca2+

Iron (II) Fe2+

Potassium K+

Topic (D)

Molecular Masses: It is defined as the sum of atomic masses of an elements present in a given molecules.

Example . Molecular mass of water (H2O) is 18 and (NaOH) is 40.

H2O > Atomic mass of Hydrogen is 1 and atomic mass of oxygen is 16 then simply add these atomic masses of both the elements

1(2)(H) + 16(O)= 18

NaOH > atomic mass of sodium(Na) is 23 , oxygen (O) 16 , hydrogen (H) 1, then simply add these atomic masses of all elements

23(Na) + 16(O) + 1(H)= 40.

Q. Calculate the molecular masses of following compounds.

(Atomic Masses are as Mg=24 , Cl=35.5 , C=12 , H=1 , O=16 , N=14 , S=32)

MgCl2, C6H12O6, NH3, HNO3, H2SO4 , HCl

How to solve percentage composition of given element in compounds

Formulla used: Given mass of element × 100

Molecular Mass of Compound

Example: Calculate the percentage composition of Hydrogen in H2O.( given mass of H is 2)

Then Percentage Composition of Hydrogen = Given mass of Hydrogen× 100 = 2 ×100 = 11.11

Molecular mass of water 18

Calculate the percentage composition of oxygen in given compounds.

NaOH , Mg(OH)2 , C6H12O6 , H2SO4 , NH3

Topic (E)

Chemical Formula: It is a symbolic representation of number of atoms present in a molecule of substance.

The significance of chemical formula is very important to finding information about chemical compounds as it tells about the element and number of substances

Example. As C6H12O6 is the chemical formula of glucose and it represent 6 carbon 12 hydrogen and 6 oxygen atom and 1 molecule of glucose.

Q> Give the Chemical formula of following compounds and also represent the number of atoms and molecules present in each case.

Ammonium Chloride Ferrous Chloride Ferric Chloride Magnesium Hydroxide Zinc carbonate Aluminum Trioxide Sulphuric Acid Washing Soda Baking Soda Methane Hydrogen Sulphide. Ammonia Marble

Hydrogen Chloride

Chemical Equation and its significance : Chemical equation is the symbolic representation of a chemical reaction in the form of symbols and formulae, wherein the reactant entities are given on the left-hand side and the product entities on the right-hand side. The coefficients next to the symbols and formulae of entities are the absolute values of the stoichiometric numbers. The first chemical equation was diagrammed by Jean Beguin.

Balancing of Chemical equation : Chemical equation should be balanced to follow the law of

conservation of mass as the number of elements in reactant side is equal to number of element

in product side,

Example: As the burning of methane would be balanced by putting a coefficient of 1 before the CH4:

1 CH4 + O2 → CO2 + H2O

Since there is one carbon on each side of the arrow, the first atom (carbon) is balanced.

Looking at the next atom (hydrogen), the right-hand side has two atoms, while the left-hand side has four. To balance the hydrogen’s, 2 goes in front of the H2O, which yields

1 CH4 + O2 → CO2 + 2 H2O

Inspection of the last atom to be balanced (oxygen) shows that the right-hand side has four atoms, while the left-hand side has two. It can be balanced by putting a 2 before O2, giving the balanced equation:

CH4 + 2 O2 → CO2 + 2 H2O

This equation does not have any coefficients in front of CH4 and CO2, since a coefficient of 1 is dropped.

16 equation from above chart

16. ………K + MgBr2…….> ……KBr + …….Mg

Practice writing chemical equations from word problems and balancing equations.

Examples:

1. Ammonium nitrate decomposes explosively to form nitrogen, oxygen, and water vapor.

2. Carbon dioxide and water reacts together to produce glucose in presence of sunlight.

3. Lead(II) nitrate undergo heating to form lead oxide , nitrogen dioxide and oxygen gas.

4. Phosphorous reacts with oxygen gas to produce diphosphorous pentoxide.

5. When calcium comes in contact with water, calcium hydroxide and hydrogen gas is

produced.

6. When Calcium carbonate reacts with Hydrogen Chloride to form calcium chloride , carbon

dioxide gas and water

7. Sodium hydroxide reacts with Hydrogen Chloride to form sodium chloride and water

8. Mercury (II) oxide decomposes to produce mercury and oxygen.

9. Zinc hydroxide reacts with phosphoric acid (H3PO4) to produce zinc phosphate and water.

10. Sulfur dioxide and oxygen combine to produce sulfur trioxide.

SUBJECT: BIOLOGY

1. From cars to food wrap and from plants to pens you can make anything and everything

from Plastics. Plastics are synthetic chemical that don't mix well with nature and can take

more than 500 years to break down in the environment.

With society’s ever-increasing focus on protecting the environment there is a new emphasis

in designing Plastics that will disappear quickly.

Make an investigatory project report on ‘BIOPLASTICS’ emphasizing the following points

a) What are bioplastics?

b) How are bioplastics made?

c) Are bioplastics good or bad?

d) Why bioplastics are not much in use?

e) Examples of bioplastics.

Instructions.

a) Write the project report on A4 sheets in your handwriting and present them in a clip

file.

b) Paste relevant colorful pictures, cutting from magazines and newspapers, etc.

c) The Project should contain topic, index, concerned information, acknowledgment and

reference.

Q2-Make an investigatory project on any one inspirational and famous environmentalist of India

/ World. The project should be made on the following guidelines :

Name and picture of the environmentalist

Age and Nationality Details of the work

Application and future prospects of his / her work

How his / her work changed the society / world

Above content not to exceed three pages.

SUBJECT: GEOGRAPHY

A. With the help of Atlas, on separate outline map of India, mark the following

features:-

1. Rivers- Ganga, Yamuna, Indus, Mahanadi, Godavari, Krishna, Kaveri

2. Islands- Andaman and Nicobar, Lakshadweep Islands

3. Mt. Peaks- K2, Anai Mudi, Nanda devi, Mizo Hills

4. Thar Desert, Northern mountains, Northern plains, Deccan plateau

5. States- Rajasthan, Gujarat, Tamil nadu, Kerala, Uttar Pradesh

B. With the help of Atlas, on separate outline map of Asia, mark the following

features:- 1. Mountain Ranges- Kunlun, Karakoram, Himalayas, Hindukush, Tien shan

2. Plateaus- Deccan, Plateau of Iran, Plateau of Yunan

3. Sea- Bering Sea, East china sea. Arabian sea, Sea of japan, Yellow sea, Black sea

4. Arctic Ocean, Pacific Ocean, Indian Ocean

5. Knot- Pamir Knot

C. With the help of different sources on internet revise the following topics:-

1. Natural Disasters- Earthquakes, Floods, Landslides, Tsunamis

2. Manmade disasters- Nuclear and chemical disasters

3. India and its physical divisions- Northern Mountains, Plains, Deserts, Deccan plateau,

Coastal Plains, Islands

4. What is Urbanisation? Its causes and effects.

5. Factors affecting Climate of India- Latitude, Altitude, Distance of Sea, The

Himalayas, Relief Features

6. Importance of forests and wildlife.

SUBJECT:MATHS

ALGEBRA

Q1 If we subtract (a - b) from (a + b), the result is

Q2The value of (5m2 – 2m) + (8m

2 + m)is

Q3 Add ab - bc, bc - ca, ca - ab

Q4The simplified form of {(-3x2 + 4xy + y

2) – (4x

2 – y

2)} is

Q5The sum of 4xy and -3xy is

Q6If we subtract s2 + 3s – 4 from 3s

2 – 5s – 3 we get

Q7The sum of 7xy + 5yz and 4yz - 2xy is

Q8The expression to be added to (5m2 – 7m + 2) to produce (7m

2 – 1) is

Q9The sum of two terms 3pq2 and 4pq

2 is

Q10If „X‟ is subtracted from 2a + 8b + 10 to get –3a + 7b + 16, then the

value of „X‟ is

Q11Add. 7xy + 5yz + 2zx and 2xy – 4yz – zx

Q12Subtract 7x - 3x2 from 4x + 8x

2.

Q13Add 4x2 + 2xy – 4 and 7x

2 – 3xy + 4.

Q14 What should be added to x2 + xy to obtain 5x

2 - xy?

Area

Q1A square has an area of 49 cm2

. The length of each of its side is

Q2 In the given figure, the area of triangle LMN is

Q3If the area of the triangle is 21 cm2 and height is 3 cm, then its base is

Q4 If the area and length of a rectangular plot are 440 m2 and 22 m respectively, find the

breadth

Q5The area of a square park whose perimeter is 320 m would be

Q6The floor of a room is square in shape. If the length of its one side is 3.4 m, then its area is

Q7If the area of a square is 576 cm2, then its side is

Q8In given figure(1), if the area of the triangle ABC is 36 cm2 and the height AD is 3 cm

then the base would be

Q9You have a square piece of cardboard that has a perimeter of 16 cm. The area of the

cardboard is

Q10If the base and height of a triangle are 4 cm and 3 cm respectively, then its area is

Q11The sides of a rectangular ground are 30 m and 120 m respectively. Its area is

Q12The area and length of a whiteboard are 1.35 m2 and 1.5 m respectively. Its breadth

is

Linear Equations

Q1 If 4 + 3(t + 2) = 10, then t is equal to

Q2 If 5t + 28 = 3, then t equals

Q3If , the value of x is

Q4If , the value of x is

Q5If -4(x - 2) = 16, the value of x is equal to

Q6Solution of is

Q7If , the value of a is

Q8If , then the value of a will be

Q9If , the value of p will be

Q10If 2q + 6 = 12, then q is equal to

Q11Find x from the equation x- 2 = 1.

Q12Find m from the equation

Q13Solve 2x =2.

Q14Find the values of p if 2p –1 = 23+p.

Q15Check whether x = 8 is a solution to the equation x - 8 = 1.

Q16Solve 3n+15 = 37.

Q17Check whether x = -2 is a solution to the equation 7x + 5 = 9 or not.

Q19Solve

Q20Solve:

Marks

Q21

Solve:

Percentage

Q1Sunita saves Rs 500 from his salary. If this is 10% of her salary, then her total salary

will be

Q2The loss in a company is decreasing from 20 lac to 5 lacs, in one year. The decreasing

loss% is

Q3If the number of illiterate persons in a country decreased from 130 lakhs to 100 lakhs

in 8 years, then the decrease % will be

Q4The value of x in 30% + x = 70% is

Q5If a storybook with market price Rs 250 was sold to a customer for Rs 280, then the

increase% will be

Q6In a village, 30% people are women, 40% are men and rest are children. The percent

of the children in the village is

Q7The price of a watch was increased from Rs 1770 to Rs 2200. The percentage increase

is

Q8We have a basket full of apples, oranges and mangoes. If 50% are apples, 30% are

oranges, then the percentage of mangoes will be

Q9

Q10Total numbers of beads in a bag are 20, if red beads are 8 and blue beads are 12, find

out the percentage of each colour of beads.

Q11

Perimeter

Q1 If the length and breadth of a rectangular field is 10 cm and 6 cm

respectively then the perimeter of the field would be

Q2An equilateral triangle has a base of 8 cm. Its perimeter is equal to

Q3A rectangle has a length of 6 cm and diagonal 10 cm. The width of the

rectangle will be

Q4A rectangular field has dimensions 84 m by 37 m. The cost of fencing its

boundary at the cost of Rs 2.50/m is

Q5The circumference of a circle of diameter 8 cm is

Q6A garden is in the shape of a rectangle. If the perimeter of the garden is

196 m and its length is 56 m then the width of the garden will be

Q7The length of a rectangle is 8 cm more than its breadth. If its perimeter is

56 cm, then its length and breadth are respectively.

Q8If s is the side of a square, then its perimeter is

Q9The perimeter of a square whose side measures 2.5 cm is

Q10If the length and breadth of a rectangle are 10 cm and 8 cm respectively,

then its perimeter (in cm) is

Q11 The measure of the boundary of a square tile is 40 mm. The length of

each side of the tile is

Q12The perimeter of a triangle is 60 cm. If two of its sides measure 20 cm

and 12 cm, then the length of the third side will be

Q13If the perimeter of a rectangle is 36 cm and the length is twice the width

then the dimensions of this rectangle are

Profit and Loss

Q1Mohan bought a T.V. set for Rs 10,000 and sold it at a profit of 10%. The profit on the

T.V. set is

Q2Akash bought a car for 75,000. He spent 9,000 on repairs and spent 1,500 on

other things. If he sold the car for 1,20,000, then the gain% will be

Q3The cost of a toy is Rs 120. If the shopkeeper sells it at a profit of 20%, then the

selling price will be

Q4 Sunita bought a music system for Rs 5,000 and sold it at a profit of 8%. The profit

amount of the music system is

Q5 A jacket with a cost price of Rs 1000 was sold for Rs 750. The loss% is

Q6 By selling a DVD. for Rs 12,000; a profit of Rs 1,500 is made. The profit% is

Q7 In a shop of ready-made garments, a dress is marked at Rs 1,350 and is available for

Rs 954. The discount given by the shopkeeper is

Q8 An almirah is marked at Rs 6,000 and is available at a discount of 12%. The sale

price of almirah is

Q9 Karan bought a cycle for Rs 3,000 and sold it at a loss of 15%. His loss amount is

Q10 A shopkeeper sells an article of 400, while he purchases it for 402. Find out loss

per cent of shopkeeper.

Q11 A shopkeeper buys a television for 5,000 and sells it at a profit of 1,200. What is

the selling prqice of the television?

Q12 What will be the cost price of a fan which is sold at 460 with a loss of 10%?

Q13 A man buys a wrist watch for 1,125 and sells it for 1,120. Find his profit or loss.

Q14 The C.P. of an air conditioner is 10,000. A loss of 10% is suffered on selling it.

Find the loss.

Q15 A man bought a microwave at 4500 and spent 1500 on transportation. If he sold

the microwave at a profit of 7%, what was its selling price?

Simple Interest

Q1If Ravi borrows Rs 750 for a period of 5 years at the rate of 5%, then the simple

interest that he has to pay, will be

Q2 If P is Principal, R is rate of interest and I is simple interest then the missing term in I

= (P R ...)/100 is

Q3The amount to be paid on 7500 at 3.5% p.a. for 1 year is

Q4If P = Rs 1200 , R= 12% per annum and T = 3 years, then simple interest would be

Q5The simple interest of Rs 8500 for 2 years at 8% p.a. is

Q6The difference between the amount and principal is said to be the

Q7If the principal amount is 1000 at 6% p.a., then the amount to be paid at the end of 3

years will be

Q8Simple interest on Rs 600 for 5 years is Rs 60. The rate of interest was

Q9The simple interest of Rs 2,500 for 3 years at 5% p.a. is

Q10 If the principal is Rs 200, then the amount to be paid at 2% p.a at the end of one

year will be

Q11The simple interest on a sum of money is 7,000 when invested for 2 years and

8,000 when invested for 3 years. Find the interest earned in one year.

Q12Find the amount to be paid back by Anuj if he borrowed 3500 and the interest is

400?

Q13Sameer borrowed some money from his friend. He gave back an amount of 25,500

at the end of the loan period. If the interest is 5,100, what amount of money did he

borrow?

Q14Shefali deposited 3000 in savings account in a bank. After a year, the balance in

her account was 3400. What is the interest paid by the bank?

Q15Manav borrowed 55,000 from his friend and paid him back 78,500 at the end of

the loan period. What amount of money did he pay as interest?

Q16Arif deposited 14,000 in a bank. After six months, the balance in his account was

14,200. What interest will be paid by the bank at the end of a year?

Q17Find the simple interest on 10,000 for 2 years at 8% per annum.

Q18At what rate per annum will 2400 amount to 3500 in 5 years?

Q19How long will it take for 4800 invested at the rate of 9% per annum simple interest

to amount 5880?

Q20 On what sum of money, the simple interest at 5% per annum for 5 years will be

800?

Q21At what rate percent will the sum of money triple itself in 20 years?

Q22Mohan took a loan of 1500 with simple interest for as many years as the rate of

interest. If he paid 735 as interest at the end of the loan period, what was the rate of

interest?

Q23Sheena took a loan of 50,000 at 2% per quarter for 18 months. Find the amount of

money she has to pay after the completion of the loan period.

Unitary Method

Q1Cost of a dozen rakhis is Rs. 36.The amount Shikha will pay if she wants to buy 7

rakhis is

Q2 If the cost of five rolls of camera film is Rs. 500, then the cost of eight such camera

rolls is

Q3 A car travels 165 km in 3 hours. In hours, it travels

Q4 The cost of 8 packets of chocolates if 3 packets cost Rs. 45, is

Q5 Fifteen post cards cost Rs 2.25. The cost of 36 such post cards would be

Q6 2 dozen of oranges cost Rs 60. The cost of 120 such oranges will be

.Q7 If a worker earns Rs 18,000 in 15 months, then he earn Rs 30,000 in

Q8 The weight of 72 books is 9 kg. The weight of 80 such books will be

Q9 What will be the cost of a quintal if 1 kg of rice costs 32.50?

Q10

Q11 Nine kg of wheat flour costs 166.50. How much flour can be purchased for 259?

Q12

SUBJECT: COMPUTER

1. Make a collage on “Usage of Internet”.

2. Apply your creativity to make something useful with e-waste i.e. used tech devices, old

computer parts, telephone cables, keyboards, mouse etc.

3. Create a Gmail-Id or Yahoo- ID and send email to your family member or friend.