Page No: 100 Thinking about the Poem   1. (i) Find, in the first stanza, three things that cannot happen in a treeless forest. (ii) What picture do these words create in your mind: “…[…]

Page No: 79 Multiple choice questions (i) Which one of the following industries uses limestone as a raw material. (a) Aluminium (b) Cement (c) Sugar (d) Jute ► (b) Cement (ii) Which one of the following[…]

Exercise 9.1 QUESTION 1 List five rational numbers between: (i) -1 and 0 Sol : Let us write — 1 and 0 as rational numbers with denominator 6 Here we take 6 because we want[…]

EXERCISE 8.3 QUESTION 1 Tell what is the prof‌it or loss in the following transactions. Also f‌ind prof‌it percent or loss percent in each case. (a) Gardening shears bought for Rs 250 and sold for[…]

EXERCISE 8.2 QUESTION 1 Convert the given fractional numbers to percent: (a) Sol : = 12.5% (b) Sol : = 5 × 25% = 125% (c) Sol : = 7.5% (d) Sol :   QUESTION[…]

Exercise 7.1    Exercise 7.2 EXERCISE  7.2 QUESTION 1 Which congruence criterion do you use in the following ? (a) Given: AC = DF, AB = DE, BC = EF Sol : By SSS congruence[…]

Exercise 7.1    Exercise 7.2 EXERCISE  7.1 QUESTION 1 Complete the following statements : 1. Two line segments are congruent if _______________. 2. Among two congruent angles, one has a measure of 70∘ , the[…]

Exercise 9(A)   Exercise 9(B)   Exercise 9(C)   Exercise 9(D) EXERCISE 9(B) Question 1  Find the S.P. when M.P. =₹ 990 and discount = 10%. Sol : We know that Selling Price = Market Price –[…]

EXERCISE 6.5 QUESTION 1 PQR is a triangle right angled at P . If PQ = 10 cm and PR = 24 cm , find QR Sol : By applying Pythagoras theorem in △PQR, (PQ)2[…]

Exercise 6.4 QUESTION 1 Is it possible to have a triangle with the following sides? (i) 2 cm , 3 cm , 5 cm (ii) 3 cm , 6 cm , 7 cm (iii) 6[…]

EXERCISE  6.2 QUESTION 1 Find the value of the unknown exterior angle x in the following diagrams: (i) x = 50° + 70° (Exterior angle theorem) x = 120° (ii) x = 65° + 45°[…]

EXERCISE  6.1 QUESTION 1 In ΔPQR, D is the mid—point of (i) is ______ . (ii) PD is ______ . (iii) Is QM = MR ? Sol : (i) Altitude (ii) Median (iii) No  […]

Exercise 5.2 QUESTION 1 State the property that is used in each of the following statements ? (i) If a || b, then ∠1 = ∠5 Sol :  Corresponding angles property   (ii) If ∠4[…]

Exercise 5.1 QUESTION 1 Find the complement of each of the following angles: The sum of the measures of complementary angles is 90°. (i) 20° Complement = 90° – 20° = 70°   (ii) 63°[…]

Exercise 4.1 QUESTION 1 Complete the last column of the table s.no Equation Value Say , whether the equation is satisfied (Yes/NO) (i) x + 3 = 0 x = 3 (ii) x + 3[…]

Exercise 2.1 Question 1 Solve : (i) Sol : (ii) Sol : (iii) Sol : (iv) Sol : (v) Sol : (vi) Sol : (vii)  Sol :  

Exercise 2.7 Question 1 Find: (i) Sol : (ii) Sol : = 0.07 (iii) Sol : = 0.62 (iv) Sol : = 10.9 (v) Sol : = 162.8 (vi) Sol : = 2.07 (vii) Sol[…]

Exercise 2.6 Question 1 Find: (i) Sol : = 1.2 (ii) Sol : = 36.8 (iii) Sol : = 13.55 (iv) Sol : = 80.4 (v) Sol : = 0.35 (vi) Sol : = 844.08[…]

Exercise 2.4 Question 1 Find : (i) Sol :  = 16   (ii) Sol :   (iii) Sol :   (iv) Sol : (v) Sol : (vi) Sol :   Question 2 Find the reciprocal[…]

Exercise 2.5 Question 1 Which is greater? (i) 0.5 or 0.05 (ii) 0.7 or 0.5 (iii) 7 or 0.7 (iv) 1.37 or 1.49 (v) 2.03 or 2.30 (vi) 0.8 or 0.88 Sol : (i) 0.5[…]

Exercise 2.1 Question 1 (i) If find the values of and Sol : By the definition of equality of ordered pairs, we have: and and and b = 1   (ii) If find the values[…]

Exercise 9.2 Question 1 Prove that the function is everywhere continuous . Sol : When , we have We know that sin x as well as the identity function x are everywhere continuous . So , the[…]

Light : is a form of energy which enables us to see objects from which it comes (or from which it reflects.) Luminous objects : Those objects which gives out their own light are called[…]

WORK AND ENERGY Whenever a force makes a body move , then work is said to be done or work is done when force produces motion. And for doing work energy is required. Work done[…]

PERIODIC CLASSIFICATION OF ELEMENTS Firstly what is element , an element is a substance containing atoms of only one type e.g Na , Au , Ca , etc . Up till now there are around[…]

HYDROCARBONS Organic compound are composed of only carbons and hydrogen are called hydrocarbons. ON THE BASIS OF STRUCTURE HYDROCARBONS ARE OF TWO TYPES  1. Acyclic or open chain hydrocarbons 2. Cyclic or closed chain hydrocarbons[…]

COAL AND PETROLEUM Firstly what is fuel ,fuel is a material that consist of energy stored in it. Most of the fuel are free carbons (coal , coke ,charcoal) or just carbon compounds (kerosene ,[…]

WORK, ENERGY AND POWER In your daily life you have seen many things like person pushing heavy box , a teacher teaching students , mom cooking food , all are said to be working .[…]

REDOX REACTIONS Chemical reaction in which electron transfer from one chemical substance to another are termed as oxidation-reduction reactions or redox reactions. You can see many examples from your daily life like production of electricity[…]

Thermodynamics The word “thermodynamics” is derived from Greek words therme (heat) and dinamics (flow or motion) . Thermodynamics mainly deals with the transformation of heat into mechanical energy and vice versa .   LIMITATIONS OF THERMODYNAMICS[…]

Straight line EXERCISE 23.1 1. Find the slopes of the lines which make the following angles with the positive direction of x-axis : (i) ​\( -\dfrac{\pi}{4} \)​ sol: m=tan​\( \theta \)​ =tan(​\( -\dfrac{\pi}{4} \)​)  = -1[…]

SOME BASIC CONCEPT OF CHEMISTRY Classification of matter on the basis of chemical properties: Matter classified into two groups pure substances and mixtures.Pure substances further divided into elements and compounds. 1. Elements : it is[…]

DOS (DISK OPERATING SYSTEM) DOS is the most popular example of single user operating system. DOS stands for Disk Operating System. Disk operating system is a ready-made program which provide various computer handling facilities through[…]

SOFTWARE AT A GLANCE As you know, software is a collection of programs and a program is a set of instructions written in a programming language.Using software, user , user interacts with the computer. It[…]

SECONDARY MEMORY As you read in previous lesson that computer have Primary memory or internal memory. Now, let us see the secondary memory.Secondary memory is also called External memory of a computer. We use secondary[…]

PRIMARY MEMORY Memory unit of a computer holds (store) all data, instructions and processed data.Memory unit of computer is classified in following two categories: 1. Primary Memory (we study it in this chapter) 2. Secondary[…]

OUTPUT DEVICES The main function of an output device id to convert the binary information inside computer in numbers and words so as to be easily understood by the user.Whatever we input the data, it[…]

INPUT DEVICES   Input devices is a device through which we feed data into the computer.When data are entered in the form of digits, alphabets and other special character, input devices converts it into their[…]

COMPUTERS AND ITS COMPONENTS   COMPUTER-MORE THAN A CALCULATING DEVICE Computer is not mere a calculating device.It is a machine that can perform both arithmetic and non-arithmetic operations like copy, move select, compare etc.It works[…]

CHARACTERISTICS OF COMPUTER Computer have become necessary thing of our lives.Computers are being used almost every field.You can see computers everywhere in banks, schools, railways, airports, laboratories , hospitals shops etc. There are some amazing[…]

CLASSIFICATION BY SIZE AND PERFORMANCE According to the purpose-wise Digital computer can be classified in to two categories: Special purpose computer Special purpose computers is designed in a way that it could perform special task.Programs[…]

CLASSIFICATION OF COMPUTERS BY TYPES The computer have been classified into three categories according to their types. 1. Analog Computers 2. Digital Computers 3. Hybrid Computers ANALOG COMPUTERS ‘Analog’ is basically a Greek Word, which[…]

HISTORICAL EVOLUTION OF COMPUTER The ascent of computer is very old.It took long duration to mature.Ancient people used stone,bones,beads etc for calculation and to keep record but as a civilization developed, people felt the need[…]

Exercise 9(A)   Exercise 9(B)   Exercise 9(C)   Exercise 9(D) COMPARING QUANTITIES EXERCISE 9(A) QUESTION 1 Express each of the following ratios in the simplest form: (a) 3 kg 500 g : 4 kg 250 g[…]

CLASSIFICATION OF ELEMENTS AND PERIODICITY IN  PROPERTIES Brief Historical Development Of Periodic Table 1.Johann Dobereiner’s (Law of triads) In between 1815 and 1829 he gave law of triads.According to which group of three elements which[…]

CUBE AND CUBE ROOTS   EXERCISE 8(A) 1.Find the cubes of : (a) 2.4 (b) 0.2.5 (c) 40 (d) 51 (e) 1.4 (f) 0.09 (g) ​\( 3\dfrac{7}{4} \)​ (h) ​\( \dfrac{6}{7} \)​ (i) ​\( 2\dfrac{18}{11} \)​ (j) ​\( 1\dfrac{6}{17}[…]

SQUARES AND SQUARE ROOTS   EXERCISE 7(A)   1.Write the unit’s digits of the following numbers: (a)93 (b)72 (c)546 (d)931 2.Without actual squaring find the value of: (a)​\( 22^2-21^2 \)​ (b)​\( 685^2-684^2 \)​ (c)​\( 108^2-107^2[…]

Exercise 5.1 Exercise 5.2  Exercise 5.3 EXERCISE 5.1 Question 1 If a matrix has 8 elements, what are the possible orders it can have? What if it has 5 elements? Sol: Order of matrix =[…]

KINEMATICS The branch of physics which deals with the study of the objects at rest and in motion is called mechanics. It is further divided into two parts are: 1.Statics Statics is the branch of[…]

UNIT AND MEASUREMENT Units of measurement are vital parts of any physical quantity. Just as the person is known by his or her name, the physical quantities are known by the units of measurement. System[…]

CUBE AND CUBE ROOTS EXERCISE 4 (A)   1.Write (T) for True or (F) for false: (i) The cube root of 8000 is 200. (ii) Each prime factor appears 3 times in its cube. (iii) ​\([…]

CUBE AND CUBE ROOTS   EXERCISE (A) 1.Find the cube of : (a) 2.4 (b) 0.25 (c) 40 (d) 51 (e) 1.4 (f) 0.09 (g) ​\( 3\dfrac{4}{5} \)​ (h) ​\( \dfrac{6}{7} \)​ (i) ​\( 2\dfrac{8}{11} \)​ (j) \( 1\dfrac{6}{17}[…]

Square and Square root EXERCISE (A)   1.Write the unit’s digits of the squares of the following numbers. (a) 93 (b) 72 (c) 546 (d) 931 2.Without actual squaring find the value of: (a) ​\( 22^2-21^2 \)​ (b)\( 685^2-684^2 \)[…]

NUMBER SYSTEM Exercise 2 (A) 1.Write down the successor of each of the following numbers : (i) 3008 (ii) 501300708 2.Write down the predecessor of each of the following numbers : (i) 84 (ii) 5000 (iii) 3007000 (iv) 506080301 3.How[…]

Exercise 1 (A) 1.Which of the following collection are sets ? If not a set , give reasons. (a) Planets in our solar system. (b) Interesting books in the library. (c) Colours of the Rainbow.[…]