Subscribe:

## Monday, January 30, 2012

### ICSE date sheet and sample paper for 2012

The Council for the Indian School Certificate Examinations or ICSE is the second largest educator for undergraduate levels. The acronym for the 10th board is ICSE and for 12th Board it is ISC. Every year lakhs of students appear for the ISCE board exams and this resource is dedicated to those youngsters and their parents.
ICSE (Class X) Specimen Question Papers
ICSE Specimen Question Papers 2012(Website.http://www.cisce.org )
English Language (English Paper - 1)
Literature in English (English Paper - 2)
Hindi
Sanskrit
Environmental Education
History & Civics (H.C.G. - Paper - 1)
Geography (H.C.G. - Paper - 2)
Mathematics
Physics (Science Paper-1)
Chemistry (Science Paper-2)
Biology (Science Paper-3)
Economics
Commercial Studies
Technical Drawing
Computer Science
Environmental Science
Art Papers I
Art Papers II
Art Papers III
Art Papers IV
Technical Drawing Applications
Home Science
Cookery
Fashion Designing
Physical Education
Yoga
Computer Applications
Economic Applications
Commercial Applications
Environmental Applications

### IX Linear Equations in Two Variables Mathematics Class Nine CBSE

1. Determine the point on the graph of the linear equation x + y=6, whose ordinate is twice its abscissa.
Q2. How many solution(s) of the equation 3x+2=2x-3 are there on the
i) Number Line ii) Cartesian plane
Q3. Draw the graph of the equation represented by the straight line which is parallel to the x-axis and 3 units above it.
Q4. Find the solutions of the linear equation x+2y=8, which represents a point on i) x axis ii) y-axis
Q5. For what values of c, the linear equation 2x+cy=8 has equal values of x and y as its solution.
Q6. Give the geometrical interpretations of 5x+3=3x-7 as an equation
i) in one variable ii) In two variables
Q7. Draw the graph of the equation 3x+4y=6. At what points, the graph cut the x-axis and the y-axis.
Q8. At what point does the graph of equation 2x+3y=9 meet a line which is parallel to y -axis at a distance 4 units from the origin and on the right side of the y-axis.
Q9. Express the following linear equations in the form ax + by + c = 0 and indicate the values of a, b and c in each case: (i) -2x + 3y = 6 (ii) x = 3y (iii) 2x = -5y
Q10. Find the value of k if x = 2, y = 1 is a solution of the equation 2x + 3y = k.
Q11. If the point (3, 4) lies on the graph of the equation 3y = ax + 7, find the value of a?
Q12. (i) Draw the graph of the linear equation using given Celsius for x-axis and Fahrenheit for y-axis.
F =(9/5)C + 32
(ii) If the temperature is 30°C, what is the temperature in Fahrenheit?
(iii) If the temperature is 95°F, what is the temperature in Celsius?
(iv) If the temperature is 0°C, what is the temperature in Fahrenheit and if the temperature is 0°F, what is the temperature in Celsius?
(v) Is there a temperature which is numerically the same in both Fahrenheit and Celsius? If yes, find it.

### Class IX Maths Assignment Area, Circles ,Constructions and Linear equations in two variables2012

Q1.  Determine the point on the graph of the linear equation x + y=6, whose ordinate is twice its abscissa.
Q2.  How many solution(s) of the equation 3x+2=2x-3 are there on the
i) Number Line            ii) Cartesian plane
Q3.  Draw the graph of the equation represented by the straight line which is parallel to the x-axis and 3 units above it.
Q4. Find the solutions of the linear equation x+2y=8, which represents a point on  i) x axis  ii) y-axis
Q5.  For what values of c, the linear equation 2x+cy=8 has equal values of x and y as its solution.
Q6. Give the geometrical interpretations of 5x+3=3x-7 as an equation
i) in one variable  ii) In two variables
Q7. Draw the graph of the equation 3x+4y=6. At what points, the graph cut the x-axis and the y-axis.
Q8. At what point does the graph of equation 2x+3y=9 meet a line which is parallel to y -axis at a distance 4 units from the origin and on the right side of the y-axis.
Q9.  P is the mid point of side BC of parallelogram ABCD such that AP bisects angle A.
Q10. Prove that bisector of any two consecutive angles of parallelogram intersect at right angles.
Q11. E and F are respectively the midpoints of non parallel sides AD and BC of trapezium. Prove that EF is parallel to AB and EF=1/2(AB+CD).
Q12.  ABCD is a rectangle in which diagonal BD bisects angle B. Show that ABCD is a Square.
Q13.  Diagonals of Quadrilateral ABCD bisect each other. If angle A = 35 degree, determine angle B.
Q14. The bisectors of angle B and angle D of quadrilateral ABCD meet CD and AB, produced at point P and Q respectively. Prove that < P+ < Q = ½(< ABC+ < ADC).
Q15. In parallelogram ABCD, AB=10cm, AD= 6cm. The bisector of angle A meets DC in A. AE and BC produced meet at F. Find the length of CF.
Q16. Evaluate: (5x+1) (x+3)-8= 5(x+1) (x+2).

Unit- Area
Q-1: Prove that the diagonals of a parallelogram divide it into four triangles of equal areas.
Q-2: Prove that triangles on the same base and between same parallels are equal in areas.
Q-3: Prove that the three straight lines joining the mid-points of the sides of a triangle divide the triangle into four triangles of equal areas.
Q-4: ABCD is trapezium with AB parallel to DC. A line parallel AC intersects AB and BC at X and Y respectively. Show that area (triangle ADX) = area (triangle ACY).
Q-5: “parallelograms on the same base and between the same parallels are equal in area.” Prove it.
Q-6: Prove that the triangles with equal areas and equal bases have equal corresponding altitudes.
Q-7: A diagonal of a parallelogram divides it into two triangles of equal areas. Prove it.
Q-8:Show that the area of a parallelogram is equal to the product of any of its sides and the corresponding altitude.
Q-9: If a triangle and a parallelogram are on the same base and between the same parallels , the area of the triangle is equal to half that of the parallelogram.
Q-10: Show that median of a triangle divides it into two triangles of equal areas.

Unit: Circle
Q-1: Two circles with centres A and B of radii 5cm and 3cm touch each other internally . If the perpendicular bisector of segment AB meets the bigger circle in P and Q , find the length of PQ.
Q-2: In a circle of radius 5cm ,AB and AC are two chords such that AB=AC=6cm . Find the length of chord BC.
Q-3: Two circles of radii 10cm and 8cm intersect and the length of the common chord is 12cm . Find the distance between their centres.
Q-4: Prove that diameter is the greatest chord in the circle.
Q-5: A,B,C and D are four points on a circle such that AB=CD. Prove that AC=BD.
Q-6: Prove that all the chords of a circle through a given point within it, the least is one which is bisected at the point.
Q-7: Two circles intersect at A and B and AC and AD are respectively the diameters of the circles. Prove that C,B and D are collinear.
Q-8: O is the circumcentre of the triangle ABC and OD is perpendicular on BC. Prove that Angle BOD=Angle A.
Q-9: Circles are described on the sides of a triangle as diameters. Prove that the circles on any two sides intersect each other on the third side.
Q-10: “Angle subtended in the major segment is obtuse” Justify your answer
Unit: Construction
Q-1: Construct a triangle ABC with base BC=4.5cm, angle B =60o and AB+AC=7.1cm.
Q-2: Construct a triangle ABC with its perimeter=11cm and base angles of 45o and 60o.
Q-3: Construct a triangle PQR with base PQ=4.2cm , angle P=45o and PR-QR=1.4cm.
Q-4: Construct a triangle ABC with base AB=4cm , angle 45o and AC+BC=7cm.
Q-5: Construct an triangle ABC with base BC=3.5cm , angle B =60o and AB-AC=1.1cm.

Q1.  Determine the point on the graph of the linear equation x + y=6, whose ordinate is twice its abscissa.
Q2.  How many solution(s) of the equation 3x+2=2x-3 are there on the
i) Number Line            ii) Cartesian plane
Q3.  Draw the graph of the equation represented by the straight line which is parallel to the x-axis and 3 units above it.
Q4. Find the solutions of the linear equation x+2y=8, which represents a point on  i) x axis  ii) y-axis
Q5.  For what values of c, the linear equation 2x+cy=8 has equal values of x and y as its solution.
Q6. Give the geometrical interpretations of 5x+3=3x-7 as an equation
i) in one variable  ii) In two variables
Q7. Draw the graph of the equation 3x+4y=6. At what points, the graph cut the x-axis and the y-axis.
Q8. At what point does the graph of equation 2x+3y=9 meet a line which is parallel to y -axis at a distance 4 units from the origin and on the right side of the y-axis.
Q9.  P is the mid point of side BC of parallelogram ABCD such that AP bisects angle A.
Q10. Prove that bisector of any two consecutive angles of parallelogram intersect at right angles.
Q11. E and F are respectively the midpoints of non parallel sides AD and BC of trapezium. Prove that EF is parallel to AB and EF=1/2(AB+CD).
Q12.  ABCD is a rectangle in which diagonal BD bisects angle B. Show that ABCD is a Square.
Q13.  Diagonals of Quadrilateral ABCD bisect each other. If angle A = 35 degree, determine angle B.
Q14. The bisectors of angle B and angle D of quadrilateral ABCD meet CD and AB, produced at point P and Q respectively. Prove that < P+ < Q = ½(< ABC+ < ADC).
Q15. In parallelogram ABCD, AB=10cm, AD= 6cm. The bisector of angle A meets DC in A. AE and BC produced meet at F. Find the length of CF.
Q16. Evaluate: (5x+1) (x+3)-8= 5(x+1) (x+2).

Unit- Area
Q-1: Prove that the diagonals of a parallelogram divide it into four triangles of equal areas.
Q-2: Prove that triangles on the same base and between same parallels are equal in areas.
Q-3: Prove that the three straight lines joining the mid-points of the sides of a triangle divide the triangle into four triangles of equal areas.
Q-4: ABCD is trapezium with AB parallel to DC. A line parallel AC intersects AB and BC at X and Y respectively. Show that area (triangle ADX) = area (triangle ACY).
Q-5: “parallelograms on the same base and between the same parallels are equal in area.” Prove it.
Q-6: Prove that the triangles with equal areas and equal bases have equal corresponding altitudes.
Q-7: A diagonal of a parallelogram divides it into two triangles of equal areas. Prove it.
Q-8:Show that the area of a parallelogram is equal to the product of any of its sides and the corresponding altitude.
Q-9: If a triangle and a parallelogram are on the same base and between the same parallels , the area of the triangle is equal to half that of the parallelogram.
Q-10: Show that median of a triangle divides it into two triangles of equal areas.

Unit: Circle
Q-1: Two circles with centres A and B of radii 5cm and 3cm touch each other internally . If the perpendicular bisector of segment AB meets the bigger circle in P and Q , find the length of PQ.
Q-2: In a circle of radius 5cm ,AB and AC are two chords such that AB=AC=6cm . Find the length of chord BC.
Q-3: Two circles of radii 10cm and 8cm intersect and the length of the common chord is 12cm . Find the distance between their centres.
Q-4: Prove that diameter is the greatest chord in the circle.
Q-5: A,B,C and D are four points on a circle such that AB=CD. Prove that AC=BD.
Q-6: Prove that all the chords of a circle through a given point within it, the least is one which is bisected at the point.
Q-7: Two circles intersect at A and B and AC and AD are respectively the diameters of the circles. Prove that C,B and D are collinear.
Q-8: O is the circumcentre of the triangle ABC and OD is perpendicular on BC. Prove that Angle BOD=Angle A.
Q-9: Circles are described on the sides of a triangle as diameters. Prove that the circles on any two sides intersect each other on the third side.
Q-10: “Angle subtended in the major segment is obtuse” Justify your answer
Unit: Construction
Q-1: Construct a triangle ABC with base BC=4.5cm, angle B =60o and AB+AC=7.1cm.
Q-2: Construct a triangle ABC with its perimeter=11cm and base angles of 45o and 60o.
Q-3: Construct a triangle PQR with base PQ=4.2cm , angle P=45o and PR-QR=1.4cm.
Q-4: Construct a triangle ABC with base AB=4cm , angle 45o and AC+BC=7cm.
Q-5: Construct an triangle ABC with base BC=3.5cm , angle B =60o and AB-AC=1.1cm.

## Friday, January 27, 2012

### CBSE MATH STUDY: ASSIGNMENT FOR THE SESSION 2011-2012 Class: VIII Maths

CBSE MATH STUDY: ASSIGNMENT FOR THE SESSION 2011-2012 Class: VIII
ASSIGNMENT FOR THE SESSION 2011-2012 Class: VIII Subject : Mathematics Term -II
Trapezium
1. The parallel sides of a trapezium are 25 cm and 11 cm, while its non parallel sides are 15cm and
13cm. find the area of the trapezium.
2. The parallel sides of a trapezium are 78 cm and 52 cm, while its non parallel sides are 28cm and
30cm. find the area of the trapezium.
3. The parallel sides of a trapezium are 12cm and 36cm respectively. Its non parallel sides are each equal to 15cm. Find the area of the trapezium.
AREA
1. Verify Euler’s formula for a) Square pyramid b) Pentagonal prism c) tetrahedron
2. The area of a rhombus is equal to the area of a triangle whose base and the corresponding altitude
are 24.8 cm and 16.5 cm respectively. If one of the diagonal of the rhombus is 22 cm, find the length of the other diagonal.
3. The floor of a rectangular hall has a perimeter 250m. If the cost of paining the four walls at the
rate of Rs 10 per m2 is Rs 1500. Find the height of the hall. Ans: 3/5 m = 0.6m
4. A room is half as long again as it is broad. The cost of carpeting the room at Rs 3.25 per m2 is Rs 175.50 and the cost of papering the walls at Rs 1.40 per m2 is Rs 240.80. If 1 door and 2 windows occupy 8m2, find the dimensions of the room.
5. A river 2m deep and 45m wide is flowing at the rate of 3 km per hour. Find the volume of water that runs into the sea per minute.
6. A closed cylinder has diameter 8cm and height 10cm. Find its total surface area and volume.
7. The volume of a metallic cylinder pipe is 748cm3 . Its length is 14 cm and external diameter 18cm. Find its thickness.
8. A cylindrical bucket, 28cm in diameter 72cm high is full of water. The water is emptied into a rectangular tank, 66cm long and 28cm wide. Find the height of the water level in the tank.
9. A cylindrical tube, open at both ends, is made of metal. The internal diameter of the tube is 10.4cm and its length is 25cm. The thickness of the metal is 8mm everywhere. Calculate the volume of the metal.
10. The difference between outside and inside surface of a cylindrical metallic pipe 14cm long is 44cm2 . If the pipe is made of 99 cm3 . Find the outside and inner radii of the pipe.
Volume and surface area.
1. A hollow cylindrical pipe is 21 dm long. Its outer and inner diameters are 10cm and 6cm respectively. Find the volume of copper used in making the pipe.
2. The height of a right circular cylinder is 10.5m. Three times the sum of the areas of its two circular faces is twice the area of the curved surface. Find the volume of the cylinder.
3. The circumference of the base of a 10m high conical tent is 44m. Calculate the length of canvas used in making the tent if width of canvas is 2m.
4. The radius and height of a cone are in the ratio 4:3 the area of the base is 154cm2. find the area of
the curved surface.
5. The volume of a metallic cylindrical pipe is 748cm3 . Its length is 14 cm and its external radius is 9 cm. Find its thickness.
6. A well of inner diameter 14m is dug to a depth of 15m. Earth taken out of it has been evenly spread all around it to a width of 7m to form an embankment. Find the height of the embankment.
7. A cloth having an area of 165m is shaped into a cylindrical tent of radius 5m. How many students can sit in the tent if a student occupies 5/7 m2 ? Find the volume of air for each student.
8. The difference between inside and outside surfaces of cylindrical tube 14cm long is 88 sq.cm. If the volume of the tube is 176 cubic cm. find the inner and outer radii of the tube.
9. The area of three adjacent faces of a cuboidal box are 120cm2, 72cm2 and 60cm2 respectively. Find the volume of the box.
10. The total surface area of a hollow cylinder which is open from both sides is 4620cm2, area of base ring is 15.5cm2 and height 7cm. Find the thickness of the cylinder.
RATIO AND PROPOTION
1. The extension in an elastic string varies directly as the weight hung on it. If a weight of 150g produces an extension of 2.8cm, what weight would produce an extension of 19.6cm?
2. A group of 120 men had provisions for 200 days. After 5 days, 30 men died due to an epidemic. How long will the remaining food lost?
3. 1200 soldiers in a fort had enough food for 28 days. After 4 days. Some soldiers were transferred to another fort and thus the food lasts for an extra 32 days. How many soldiers left the fort?
4. If 12 men or 15 woman can finish a piece of work in 66 days. How long will 2 men and 3 woman take to finish the work?
5. If 5 men or 7 women earn Rs 525 per day, how much would 7 men and 13 women earn per day?
6. In an army camp of 1400 men, these is enough food to last for 18 days if each man consumes 396g per day. How many men should leave the camp so that the same food may last for 21 days with each man having 432g per day?
Bar Graph
1. The following table shows that the favorite sports of 250 students of a school. Represent the data by a bar graph.
Sports                   Cricket     Foot ball      Tennis      Badminton      Swimming
No of students          75             35              50                25                65
2. Given below is a table which shows the year wise strength of a school. Represent this data by a bar graph.
Year                   2001 -02  2002 -03   2003 -04    2004 -05       2006 -07
No of students       800       975             1100           1400          1625
3. The air distances of four cities from Delhi ( in km) are given below. Represent the data by a bar graph.
Distance from Delhi in Km  1340       1100              1700           1220
4. The following is the distribution of weights in kg of 52 persons:
Weight in kg      30 – 40   40 – 50       50 – 60         60 – 70      70 – 80
Persons                10       15                   17               6                4
5. What is the lower limit of class 50 – 60?
6. Find the class mark of the classes 40 – 50, 50 – 60
7. What is the class size?
Pie Chart
1. The number of students in a school speaking different languages is given below. Present the data
in a pie chart
Language                Hindi     English    Marathi     Bengali       Tamil
No of students              40        12            9               7             4
2. The number of hours spend by a school boy on various activities on a working day are given below.
Activity             School       Homework     Play    Sleep        Others
No of hours         8                  4              3           7                3

3. Draw a pie chart for the following data of the investment pattern in a five year plan:
Agriculture      Irrigation       Small industries Transport       Power       Social service
14%                  16%                29%                  17%         16%             8%
Probability
1. A coin is tossed 500 times and we get head;285times, tail;215 times, when a coin is tossed at random, what is the probability of getting i) a head ii) a tail?
2. Two coins are tossed 400 times and we get two heads ; 112 times, one head : 160 times, zero head : 128 times when two coins are tossed at random, what is the probability of getting
3. Three coins are tossed 200 times and we get three heads: 39 times , two heads 58 times , one head; 67 times, 0 head ;36 times. When three coins are tossed at random what is the probability of getting
4. Two coins are tossed simultaneously 500 times, we get two heads 105 times, one head 275 times and no head 120 times. Find the probability of getting i) 2 tails ii) one tails iii) 2 heads.
5. All kings, jacks and diamonds have been removed from a pack of cards and the remaining cards are well shuffled. A card is drawn at random. Find the probability that it is (i) a red queen (ii) a face card (iii) a diamond (iv) a black card.
6. The shoppers who come to a departmental store are marked as :
man(M), woman(W), boy (B)or girl ( G).
The following list gives the shoppers who came during the first hour in the morning:
W W M W G W M W B W G M W M B G B W G W M G W M W G M W B W M W G W MW G M W B G W M W W M W G W M W G W M W G W M W W .
Make a frequency distribution table using tally marks.
7. A box contains 17 cards numbered 1,2,3,4,……17. A card is drawn at random from the box. Find the probability that the number on the card is
i) odd
ii) even
iii) prime
iv) divisible by 3
v) divisible by 2 and 3 both
vi) divisible by 4 or 7
vii) divisible by 2 or 3.
8. Numbers 2 to 10 are written on ten separate slips( one number on one slip), kept in a box and mixed well. One slip is chosen from the box without looking onto it. What is the probability of.
i) getting a number 6?
ii) getting a prime number
iii) getting a number greater than 5?
Graph
1. Plot the following points on the graph paper and name the quadrant in which it lies
(4, -2 ) (-1 ,3) ( 0, -1 ) ( 5, -2) ( 2, 1 ) ( -5, -3 ) and (-2, 0)
2. Draw the graph of the following equations.
i) 3x +2y =5 ii) y – 3x =2
3. Solve the following system of linear equations graphically.
a) 4x – 5y – 20 and 3x + 5y – 15 = 0
b) x + 2y = 3 and 4x = 3Y = 2.
1. Construct a quadrilateral ABCD given that
AB = 3.7cm, BC = 3.8 cm, CD = 4.3 cm, DA = 4.6 cm and ∠ D =75
2. Construct a quadrilateral ABCD given that
BC=4.5 cm, AB=4cm, ∠ B=75 ∠ A=90 and ∠ C=120
3. Construct a quadrilateral ABCD in which
AB=BC=5.5cm, CD=4cm, DA=6.3cm and AC=9.4cm. Measure  BD.
where A=65, B=105, C=75, BC=5.7 cm and CD=6.8 cm.
5. Construct a quadrilateral PQRS in which
PQ=6 cm, QR=5.6 cm, RS=2.7 cm, ∠ Q=45 and ∠ R= 90
6. Construct a parallelogram with diagonals 5.4 cm and 6.2 cm and the angle included by the two diagonals is 45
7. Construct a parallelogram ABCD using only ruler and compass, such that AB=6cm, BC=3cm and angle B=45. Write the steps of construction in brief.

8. Construct a rhombus ABCD using only ruler and compass, such that the side of the rhombus is 4 cm and one of its angles is 30. Write the steps of construction in brief.
9. Construct a trapezium ABCD in which AB=6 cm, BC= 4 cm, CD=3.2 cm ∠ B=75 and DC||AB.
10. Draw a trapezium ABCD in which AB//DC, AB = 7 cm, BC = 5cm, AD = 6.5 cm and ∠ B = 60
PARALLELOGRAM
1. Two adjacent angles of a parallelogram are as 2:3. Find the angles
2. Prove that the opposite sides of a parallelogram are equal.
3. Prove that in a parallelogram diagonals bisect each other.
4. In the adjacent figure, ABCD is a parallelogram and line segments AE and CF bisect the angles A and C respectively. Show that AE // CF.
5. Two lines AC and BD, 5cm each bisect each other. If A,B,C,D are joined what type of quadrilateral is formed. Justify your answer.
6. ABCD is a parallelogram in which AB= 2AD and p is the midpoint of AB, then Find ∠CPD.
7. In a parallelogram ABCD, if AB= 2x+5, CD= y+1 AD=y+5 and BC=3x-4, then find the ratio of AB:BC.
8. ABCD is a parallelogram whose diagonals intersect each other at O. A line segment EOF is drawn to meet AB at E and DC at F. Prove that OE = OF.
9. ABCD is a parallelogram in which AB is produced to E so that BE=AB. Prove that ED bisects BC.
10. PQRS is a rectangle. PR is a diagonal. QM & SN are perpendiculars drawn from Q & S on PR. Prove that QM = SN.
1. ABCD is a quadrilateral in which AB=AD and BC=DC. Prove that AC bisects ∠A and ∠C.
2. If angles P, Q, R and S of the quadrilateral PQRS taken in order and in the ratio 3:7:6:4 then show that PQRS is a trapezium.
3. In a quadrilateral ABCD, the line segments bisecting∠ C and ∠D meet at E. Prove that ∠A+∠B =2∠CED
4. If bisectors of ∠A and ∠B of a quadrilateral ABCD intersect each other at P , of ∠B and ∠ C at Q, of ∠C and ∠D at R and ∠ D and ∠A at S, then show that PQRS is a quadrilateral whose opposite angles are supplementary.
5. In a quadrilateral ABCD, the bisectors of < A and < B meet in a point P. If ∠ C = 100 and ∠ D = 60, find the measure of ∠ APB

### VII Science Chemistry : Water : A Precious Natural Resource

The year 2003 was observed as the INTERNATIONAL YEAR OF FRESHWATER to make people aware of this dwindling natural resource. 22nd MARCH is celebrated as the WORLD WATER DAY.

Q. Fill in the blanks with the appropriate answers:
(a) People obtain ---------through tube wells and hand pumps.[groundwater]
(b) Three forms of water are solid, liquid and ---------[vapour.]
(c) The water bearing layer of the earth is ----------[ aquifer]
(d) The process of water seepage into the ground is called ---------[ infiltration.]
(e) The process of changing of water into its vapour is called---------[ evaporation.]
(f) The process of changing water vapour into water is called ---------[condensation.]
(g) No rainfall for a year or more may lead to ---------- in that region.[drought]
(h) Excessive rains may cause ----------- [flood.]
Q. So much of water available on our planet Earth, but why do we still feel a shortage of water?
Ans: 75% of our Earth is made of water but only 3% of it is fresh water. Hence only a fraction is fit for human consumption and we still feel a shortage of water.
Most of the water that exists on the earth is in the seas and oceans which is highly salty.
Q. What are main sources of water?
Ans:    a. Rainwater                          b. Glaciers, ice and snow
c. River water                      d. Sea and Ocean water
e. Lake and Pond water
Q. What are three states of water?
Ans: As Solid – In the form of ice crystals, snow, ice pellets, hail, and frost
As Liquid: In the form of rain and dew
As Gas : In the form of Water vapour
Q. What is wter cycle?
Ans: The continuous circulation of water in nature is called water cycle. It is also called the hydrological cycle
Q: What is water table?
Ans: A level where all the space between particles of soil and gaps between rocks are filled with water. The upper limit of this layer is called the water table.
Q. What do you mean by aquifer?
Ans: Some places groundwater is stored between layers of hard rock. This is called aquifer. Water in the aquifers can usually be pumped out with the help of tube wells or hand pumps .
Q. What are causes of depletion of water table?
Ans: a. Scanty rainfall and hot winds are natural forces that may deplete the water table
b. Deforestation, increased population, rapid urbanization, overgrazing by cattle, excess tapping of ground water are human causes that deplet water.
c. Commercialization of water resources.
Q. What is desalination. Explain.
Ans: Desalination is an artificial process by which saline water ( sea water) is converted to fresh water.
The most common desalination processes are :
1. Distillation :The process in which both evaporation and condensation go side by side is called distillation. Water obtained through distillation is called distilled water. This water is normally pure enough for use in school science and medical laboratories.
2. Reverse osmosis: The process of forcing water under pressure through a semi permeable membrane whose tiny pores allow water to pass but exclude most salts and minerals.
Q. How can we conserve water?
Ans: Water conservation is process of preventing wastage of water, using water carefully and recharging ground water. Water conservation can be done by :-
i) Repairing leaking pipes and taps.
ii) Not wasting water during brushing teeth, shaving, bathing, washing clothes and during other activities.
iii) Rainwater harvesting.
iv) By drip irrigation of plants.
Q. What do you understand by anomalous expansion of water?
Ans: When water at room is cooled, it contract until reaches 40c and then starts expanding. This strange behavior of water is called anomalous expansion of water.
Q. Why ice floats on water?
Ans: Ice is lighter than water so floats on water.
Q. Why water piper burst cooler part of world in winter?
Ans: Water keeps expanding from 4C to 0 C and occupies more space in form of ice and pipe burst out.
Q. What is specific heat capacity of substance?
Ans: The amount of heat required to raise the temperature of substance is known as specific heat capacity of substance.
Q. Why water used as an excellent cooling agent in car engine?
Ans: Water has high specific heat capacity of substance and takes longer time to heat up.
Q. Why water is called universal solvent?
Ans: A large number of substances dissolve in water so it is called universal solvent. A liquid that dissolve another substance (solute) to form solution is called solvent.
Q. What is drip irrigation?
Ans: It is a method of watering plants using narrow pipes through which water drips into the base of the plants

NCERT CBSE Class VII Science Chemistry : Water : A Precious Natural Resource
 Water : Precious Natural Resource Water : Precious Natural Resource Waste water story Electric Current and Circuit Light Mirror and Lens Pollution Of Air And Water

### chemistry adda:CBSE: Water 'A precious resources' CBSE Class VI Science...

Q. Why are we left only tiny fraction of water for use even if about 75 % of the earth surface is covered with water.
Ans: This is because most of the water about 97% of surface water is in sea and ocean as salty water that is unfit for domestic and agricultural use.
Q. What are the various uses of water?
Ans: Water is used for various activities such as agriculture, industries, cooking, cleaning utensils,
bathing, washing clothes, and, most importantly, for drinking.
Q. What are the three state of water?
Ans: There are three states of water
a. Solid state: ice, snow and hail           b. liquid: Rain, river, sea   c. Gaseous: Water vapour
Q what is water cycle?
Ans: The circulation of water from atmosphere to the earth and vice versa is called the water cycle.
Q.What is evaporation?
Ans: The water present on the surface of the ocean evaporates by the sun’s heat. This process of conversion of water from liquid state to vapour state is called evaporation.
Q what is transpiration?
Ans: The excess water in plants evaporates through stomata of leaves and the stem into the air. This process is called transpiration.
Q. How cloud is formed?
Ans: The evaporated water above the earth surface is carried away by warm air. As the warm air moves higher from the surface of the Earth, it starts to cool down. It is because the water vapour present starts to condense to form tiny water droplets. These droplets float in the air and form cloud
Q. What is precipitation?
Ans: When clouds rub together heat is produced that melt the cloud into droplets. These droplets collect to form bigger drops of water. Some of them may become too heavy fall down as rain. This process is known as precipitation.
Q .What do you mean by infiltration?
Ans: The water from rain, rivers, lakes and ponds seeps through the soil and fills the space below the ground. The process of seeping of water through the soil is called infiltration
Q. What do you mean by aquifer?
Ans: Some places groundwater is stored between layers of hard rock. This is called aquifer. Water from aquifers is pumped and taken out through hand pumps and tube wells.
Q. How can we conserve water?
Ans: Water conservation is process of preventing wastage of water, using water carefully and recharging ground water. Water conservation can be done by :-
i) Repairing leaking pipes and taps.
ii) Not wasting water during brushing teeth, shaving, bathing, washing clothes and during other activities.
iii) Rainwater harvesting.
iv) By drip irrigation of plants.
Q. Fill in the blanks with the appropriate answers:
(a) People obtain ---------through tube wells and hand pumps.[groundwater]
(b) Three forms of water are solid, liquid and ---------[vapour.]
(c) The water bearing layer of the earth is ----------[ aquifer]
(d) The process of water seepage into the ground is called ---------[ infiltration.]
(e) The process of changing of water into its vapour is called---------[ evaporation.]
(f) The process of changing water vapour into water is called ---------[condensation.]
(g) No rainfall for a year or more may lead to ---------- in that region.[drought]
(h) Excessive rains may cause ----------- [flood.]

## Thursday, January 26, 2012

### CBSE_NCERT_Free Question Papers For Class 7th Cbse Maths

CBSE MATH STUDY: CBSE 7th Maths Question Papers |Sample Papers

7th Ratio and Proportion

Complete the following statements using the help box:

1. The comparison of two quantities of the same kind by means of division is termed as ____.

2. The two quantities to be compared are called the ________ of the ratio.

3. The first term of the ratio is called the _________ and the second term is called the _______.

4. In a ratio, only two quantities of the __________ unit can be compared.

5. If the terms of the ratio have common factors, we can reduce it to its lowest terms by cancelling the
_____.

6. When both the terms of a ratio are multiplied or divided by the same number (other than zero) the
ratio remains _________ .The obtained ratios are called__________.

7. In a ratio the order of the terms is very important. (Say True or False)

8. Ratios are mere numbers. Hence units are not needed. (Say True or False)

9. Equality of two ratios is called a __________. If a,b;c,d are in proportion, thena:b::c:d .

10. In a proportion, the product of extremes =___________

Help Box:

1) Ratio 2) terms 3) antecedent, consequent 4) same 5) common terms 6) unchanged, equivalent ratios
7) True 8) True 9) proportion 10) product of means

1. Find 5 equivalent ratios of 2:7

2. Reduce 270 : 378 to its lowest term.

3. Find the ratio of 9 months to 1 year

4. If a class has 60 students and the ratio of boys to girls is 2:1, find the number of boys and girls.

5. A ribbon is cut into 3 pieces in the ratio 3: 2: 7. If the total length of the ribbon is 24 m, find the length
of each piece.

6. The ratio of boys to girls in a class is 4 : 5. If the number of boys is 20, find the number of girls.

7. If A : B = 4 : 6, B : C = 18 : 5, find the ratio of A : B : C.

8. A bronze statue is made of copper, tin and lead metals. It has1/10 of tin , 1/4of lead and the rest
copper. Find the part of copper in the bronze statue.

7th Direct variation and indirect variation

In direct variation, when a given quantity (x) is changed in some ratio then the other quantity(y) is also
changed in the same ratio. Then x/ y = constant

In Indirect variation, when a given quantity (x) is changed in some ratio then the other quantity(y) is do
not changed in the same ratio. Then xy = constant

Þ It can be stated that if two quantities vary inversely, their product is a constant

i) If the cost of 8 kgs of rice is Rs 160, then the cost of 18 kgs of rice is

(A) Rs.480 (B) Rs 180 (C) Rs 360 (D) Rs 1280

ii) If the cost of 7 mangoes is `35, then the cost of 15 mangoes is

(A) Rs 75 (B) Rs 25 (C) Rs 35 (D) Rs 50

iii) A train covers a distance of 195 km in 3 hrs. At the same speed, the distance travelled in 5 hours is

(A) 195 km. (B) 325 km. (C) 390 km. (D) 975 km.

iv) If 8 workers can complete a work in 24 days, then 24 workers can complete the same work in

(A) 8 days (B) 16 days (C) 12 days (D) 24 days

v) If 18 men can do a work in 20 days, then 24 men can do this work in

(A) 20 days (B) 22 days (C) 21 days (D) 15 days

1. If x varies directly as y, complete the given tables:
 x 1 1 9 15 y 2 10 16
2. If x varies inversely as y, complete the given tables:

 x 20 10 40 50 y 50 250

3. A car travels 360 km in 4 hrs. Find the distance it covers in 6 hours 30 mins at the same speed

4. 7 men can complete a work in 52 days. In how many days will 13 men finish the same work?

5. A book contains 120 pages. Each page has 35 lines . How many pages will the book contain if every
page has 24 lines per page?

6. A car travels 60 km in 45 minutes. At the same rate, how many kilo metres will it travel in one hour?

7. A car takes 5 hours to cover a particular distance at a uniform speed of 60 km / hr. How long will it take to cover the same distance at a uniform speed of 40 km / hr?

8. 150 men can finish a piece of work in 12 days. How many days will 120 men take to finish the same work?

9. A troop has provisions for 276 soldiers for 20 days. How many soldiers leave the troop so that the provisions may last for 46 days?

10. A book has 70 pages with 30 lines of printed matter on each page. If each page is to have only 20 lines of printed matter, how many pages will the book have?

11. There are 800 soldiers in an army camp. There is enough provisions for them for 6o days. If 400 more soldiers join the camp, for how many days will the provisions last?

12. A wheel makes 48 revolutions in 3 seconds. How many revolutions does it make in 30 seconds?

7th Percentage

The word ‘Percent’ is derived from the Latin word ‘Percentum’, which means ‘per hundred’ or ‘hundredth’ or ‘out of 100’.

• Percentage also means ‘percent’.

• Symbol used for percent is %

• Any ratio x : 100 is called ‘Percent’.

1) Write the following as a percent: (i) 20:100 (ii) 100:93(iii)100/100 (iv)0.07

2) Write the following percent as a ratio: (i) 43% (ii) 17 1/2(iii) 5% (iv) 33 1/3 %

3) Write the following percent as a fraction: (i) 25% (ii) 12 1/2% 2 (iii) 33%

4) 9/10 of your blood is water. What % of your blood is not water.

5)  In a class of 35 students, 7 students were absent on a particular day. What percentages of the students were absent?

5. Ram bought 36 mangoes. 5 mangoes were rotten. What percentage of the mangoes was rotten?

6. In a class of 50, 23 were girls and the rest were boys. What is the percentage of girls and the percentage of boys?

7. Ravi got 66 marks out of 75 in Mathematics and 72 out of 80 in Science. In which subject did he score more?

8. Express as a decimal (a) 25.7% (b) 15%

9. Find the value of (a)% 1/2 of 200. (b) 0.75% of 40 kg.

10. In 2011, the population of a town is 1,50,000. If it is increased by 10% in the next year, fi nd the
population in 2012.

11. The percentage of literacy in a village is 47%. Find the number of illiterates in the village, if the population is 7,500.

12. Is it true? 20% of 25 is same as 25% of 20.

13. The tax in a restaurant is 1.5% of your total bill.

a) Write the tax % as a decimal.
b) A family of 6 members paid a bill of ` 750. What is the tax for their bill amount?

c) What is the total amount that they should pay at the restaurant?

14. Complete these

1) Any fraction with its denominator 100 is called __________

2)1/2 = -----------% 3) 35% = ------------ ( in fraction)

4) 0.05 = ----------------% 5)1/4 = ----- %

7th Profit and Loss

The price at which any one buys goods at the market is called the Cost Price(C.P.).

The price at which one can sell the goods at the market is called the Selling Price (S.P.).

Additional amount given or taken for CP is called the profit.

i) If the cost price of a bag is Rs. 575 and the selling price is Rs.625, then there is a profit of Rs.

(A) 50 (B) 575 (C) 625 (D) none of these

ii) If the cost price of the box is Rs.155 and the selling price is Rs.140, then there is a loss of Rs.

(A) 155 (B) 140 (C) 15 (D) none of these

iii) If the selling price of a bag is `235 and the cost price is `200, then there is a

(A) profit of Rs.235 (B) loss of Rs.3 (C) profit of Rs.35 (D) loss of Rs.200

iv) Gain or loss percent is always calculated on

(A) cost price (B) selling price (C) gain (D) loss

v) If a man makes a profit of Rs.25 on a purchase of Rs.250, then profit% is

(A) 25 (B) 10 (C) 250 (D) 225

1. Sanjay bought a bicycle for Rs. 5,000. He sold it for Rs.600 less after two years. Find the selling price and the loss percent.

2. A fruit seller bought 8 boxes of grapes at Rs.150 each. One box was damaged. He sold the remaining boxes at Rs.190 each. Find the profit / loss percent.

3. A shop keeper bought 10 bananas for `100. 2 bananas were rotten. He sold the remaining bananas at the rate of Rs. 11 per banana. Find his gain or loss % 6. A shop keeper purchased 100 ball pens for Rs. 250. He sold each pen for Rs. 4. Find the profit percent.

7. A vegetable vendor bought 40 kg of onions for Rs. 360. He sold 36 kg at Rs. 11 per
kg. The rest were sold at Rs. 4.50 per kg as they were not very good. Find his profit / loss Percent.

8. A trader mixes two kinds of oil, one costing Rs. 100 per Kg. and the other costing `80 per Kg. in the ratio 3: 2 and sells the mixture at Rs. 101.20 per Kg. find his profit or loss percent.

9. Sathish sold a camera to Rajesh at a profit of 10 %. Rajesh sold it to John at a loss of 12 %. If John paid Rs. 4,840, at what price did Sathish buy the camera?

10. The profit earned by a book seller by selling a book at a profit of 5% is Rs. 15 more than when he
sells it at a loss of 5%. Find the Cost Price of the book.

7th Simple Interest

1. Radhika invested Rs.5,000 for 2 years at 11 % per annum. Find the simple interest and the amount received by him at the end of 2 years.

2. Find the simple interest and the amount due on Rs. 7,500 at 8 % per annum for 1 year 6 months.

3. Find the simple interest and the amount due on Rs. 6,750 for 219 days at 10 % per annum.

4. Rahul borrowed Rs. 4,000 on 7th of June 2006 and returned it on 19th August2006. Find the amount he paid, if the interest is calculated at 5 % per annum

5. Find the rate percent per annum when a principal of Rs. 7,000 earns a S.I. of Rs.1, 680 in 16 months.

6. Vijay invested Rs.10, 000 at the rate of 5 % simple interest per annum. He received Rs.11, 000 after some years. Find the number of years.

7. A sum of money triples itself at 8 % per annum over a certain time. Find the number of years.

8. A certain sum of money amounts to Rs.10, 080 in 5 years at 8 %. Find the principal

9. A certain sum of money amounts to Rs. 8,880 in 6 years and Rs. 7,920 in 4 years respectively. Find the principal and rate percent.

10. Find the principal that earns `250 as S.I. in 21/2 years at 10 % per annum.

11. In how many years will a sum of Rs. 5,000 amount to Rs.5,800 at the rate of 8 % per annum.

12. A sum of money doubles itself in 10 years. Find the rate of interest.

13. A sum of money doubles itself at 121/2 % per annum over a certain period of time. Find the number of years.

14. A certain sum of money amounts to Rs. 6,372 in 3 years at 6 % Find the principal.

15. A certain sum of money amounts to Rs. 6,500 in 3 years and Rs. 5,750 in 11/2years respectively. Find the principal and the rate percent?

16. Find the rate per cent at which, a sum of money becomes 9/4 times in 2 years.

17) If Ram needs Rs. 6, 00,000 after 10 years, how much should he invest now in a bank if the bank pays 20 % interest p.a?