CLASS-8 SUBJECT MATHS (FINALS-E) CHAPTER-11(EXERCISE11.4) MENSURATION.

EVENTS CONVENT HIGH SCHOOL

27/01/2022      CLASS- 8   SESSION 2021-22
SUBJECT : MATHS

CHAPTER-11 (EXERCISE 11.4)
MENSURATION

______________________________________

 Question 1.Given a cylindrical tank, in which situation will you find the surface area and in which situation volume.

(a) To find how much it can hold.
(b) Number of cement bags required to plaster it.
(c) To find the number of smaller tanks that can be filled with water from it.
Solution:
(a) In this situation, we can find the volume.
(b) In this situation, we can find the surface area.
(c) In this situation, we can find the volume.

 Question 2.Diameter of cylinder A is 7 cm, and the height is 14 cm. Diameter of cylinder B is 14 cm and height is 7 cm. Without doing any calculations can you suggest whose volume is greater? Verify it by finding the volume of both the cylinders. Check whether the cylinder with greater volume also has greater surface area?

Solution:
Cylinder B has a greater volume.
Verification:
Volume of cylinder A = πr2h

Question 3.Find the height of a cuboid whose base area is 180 cm2 and volume is 900 cm3.

Solution:
Given: Area of base = lb = 180 cm2
V = 900 cm3
Volume of the cuboid = l × b × h
900 = 180 × h
h = 5 cm
Hence, the required height = 5 cm.

Question 4.A cuboid is of dimensions 60 cm × 54 cm × 30 cm. How many small cubes with side 6 cm can be placed in the given cuboid?

Solution:
Volume of the cuboid = l × b × h = 60 cm × 54 cm × 30 cm = 97200 cm3
Volume of the cube = (Side)3 = (6)3 = 216 cm3
Number of the cubes from the cuboid

Hence, the required number of cubes = 450.

 Question 5.Find the height of the cylinder whose volume is 1.54 m3 and the diameter of the base is 140 cm.

Solution:
V = 1.54 m3, d = 140 cm = 1.40 m
Volume of the cylinder = πr2h

Hence, the height of cylinder = 1 m.

Question 6.A milk tank is in the form of a cylinder whose radius is 1.5 m and length is 7 m. Find the quantity of milk in litres that can be stored in the tank.

Solution:
Here, r = 1.5 m
h = 7 m
.’. Volume of the milk tank = πr2h
= 227 × 1.5 × 1.5 × 7
= 22 × 2.25
= 49.50 m3
Volume of milk in litres = 49.50 × 1000 L (∵ 1 m3 = 1000 litres)
= 49500 L
Hence, the required volume = 49500 L.

 Question 7.If each edge of a cube is doubled,

(i) how many times will it be surface area increase?
(ii) how many times will its volume increase?
Solution:
Let the edge of the cube = x cm
If the edge is doubled, then the new edge = 2x cm
(i) Original surface area = 6x2 cm2
New surface area = 6(2x)2 = 6 × 4x2 = 24x2
Ratio = 6x2 : 24x2 = 1 : 4
Hence, the new surface area will be four times the original surface area.

(ii) Original volume of the cube = x3 cm3
New volume of the cube = (2x)3 = 8x3 cm3
Ratio = x3 : 8x3 = 1 : 8
Hence, the new volume will be eight times the original volume.

Question 8.Water is pouring into a cuboidal reservoir at the rate of 60 litres per minute. If the volume of the reservoir is 108 m3, find the number of hours it will take to fill the reservoir.

Solution:
Volume of the reservoir = 108 m3 = 108000 L [∵1 m3 = 1000 L]
Volume of water flowing into the reservoir in 1 minute = 60 L
Time taken to fill the reservoir

Hence, the required hour to fill the reservoir = 30 hours.

CLASS-8 SUBJECT MATHS (FINALS.E) CHAPTER-11 (EXERCISE11.3) MENSURATION

  EVENTS CONVENT HIGH SCHOOL

25/01/2022      CLASS- 8   SESSION 2021-22
SUBJECT :MATHS

CHAPTER-11 (EXERCISE 11.3)

MENSURATION

______________________________________

 Question 1.There are two cuboidal boxes as shown in the figure. Which box requires the lesser amount of material to make?

Solution:
(a) Volume of the cuboid = l × b × h = 60 × 40 × 50 = 120000 cm3
(b) Volume of cube = (Side)3 = (50)3 = 50 × 50 × 50 = 125000 cm3
Cuboidal box (a) requires lesser amount of material.

Question 2.A suitcase with measures 80 cm × 48 cm × 24 cm is to be covered with a tarpaulin cloth. How many metres of tarpaulin of width 96 cm is required to cover 100 such suitcases?
Solution:
Measurement of the suitcase = 80 cm × 48 cm × 24 cm
l = 80 cm, b = 48 cm and h = 24 cm
Total surface area of the suitcase = 2[lb + bh + hl]
= 2 [80 × 48 + 48 × 24 + 24 × 80]
= 2 [3840 + 1152 + 1920]
= 2 × 6912
= 13824 cm2
Area of tarpaulin = length × breadth = l × 96 = 96l cm2
Area of tarpaulin = Area of 100 suitcase
96l = 100 × 13824
l = 100 × 144 = 14400 cm = 144 m
Hence, the required length of the cloth = 144 m.

Question 3.Find the side of a cube whose surface area is 600 cm2?
Solution:
Total surface area of a cube = 6l2
6l2 = 600
l2 = 100
l = √100 = 10 cm
Hence, the required length of side = 10 cm.

Question 4.Rukhsar painted the outside of the cabinet of measure 1 m × 2 m × 1.5 m. How much surface area did she cover if she painted all except the bottom of the cabinet?

Solution:
l = 2 m, b = 1.5 m, h = 1 m
Area of the surface to be painted = Total surface area of box – Area of base of box
= 2 [lb + bh + hl] – lb
= 2[2 × 1.5 + 1.5 × 1 + 1 × 2] – 2 × 1
= 2[3 + 1.5 + 2] – 2
= 2[6.5] – 2
= 13 – 2
= 11 m2
Hence, the required area = 11 m2.

Question 5.Daniel is painting the walls and ceiling of a cuboidal hall with length, breadth and height of 15 m, 10 m and 7 m respectively. From each can of paint 100 m2 of the area is painted. How many cans of paint will she need to paint the room?
Solution:
Surface area of a cuboidal hall without bottom = Total surface area – Area of base
= 2 [lb + bh + hl] – lb
= 2 [15 × 10 + 10 × 7 + 7 × 15] – 15 × 10
= 2[150 + 70 + 105] – 150
= 2 [325] – 150
= 650 – 150
= 500 m2
Area of the paint in one can = 100 m2
Number of cans required = 500100 = 5 cans.

CLASS-6 SUBJECT SOCIAL SCIENCE CHAPTER-11 BUILDINGS PAINTINGS AND BOOKS

 EVENTS CONVENT HIGH SCHOOL

10/01/2022      CLASS- 6     SESSION 2021-22
SUBJECT :SOCIAL SCIENCE 

CHAPTER-11
BUILDINGS PAINTINGS AND BOOKS

______________________________________

I.MULTIPLE CHOICE QUESTIONS

Choose the correct option to complete the statements given below:

(i) The iron Pillar is situated at………………
(a) Junagarh
(b) Mehrauli
(c) Aihole
(d) Ahmedabad.

(ii) The height of the Iron Pillar is …………….
(a) 7.2 m
(b) 8.2 m
(c) 9.2 m
(d) 10.2 m.

(iii) The small box placed at the centre or heart of the stupa is known as a………………………
(a) Relic casket
(b) Sacred box
(c) Trunk
(d) None of the above.

(iv) The Puranas contained stories about …………………
(a) Kings and queens
(b) Gautam Buddha
(c) Mahatma Gandhi
(d) Gods and goddesses.

(v)  Sanskrit Ramayana is written by ………………
(a) Valmiki
(b) Vyasa
(c) Tulsidas
(d) Vishnu Sharma.

Answer:
(i) – (b), (ii) – (a), (iii) – (a), (iv) – (d), (v) – (a).

II.FILL IN THE BLANKS

Fill in the blanks with appropriate words to complete each sentence.

1. The ……….  at Aihole was built about 1400 years ago
2. The small box placed at the centre of the stupa contains bodily remains of the  and his followers.
3. The……. were recited in temples by priests and people came to listen to them.
4. Both the……….. and the…………. are supposed to have been composed by Vyasa.
5. developed a scientific explanation for eclipses.

Answer:

1. Durga temple
2. Buddha
3. Vedas
4. Puranas, Mahabharata
5. Aryabhatta

III.TRUE/FALSE

State whether these sentences are true (T) or false (F).

1. Most temples of this period had a hall like structure known as the mandapa.
2. Mahabalipuram and Aihole are known for the finest stone temples.
3. Merchant and farmers usually decided to build stupas and temples during this period.
4. The Tamil epic the Silappadikaram was composed by a poet named Ilango.
5. Meghaduta is a famous poem composed by Tulsidas.

Answer:

1. True
2. True
3. False
4. True
5. False

IV.MATCHING SKILL

Match the items in column A correctly with those given in column B.

Ans. (i)—(b), (ii)—(d), (iii)—(a), (iv)—(e), (v)—(c).

V. VERY SHORT ANSWER TYPE QUESTIONS

1. When was the Iron Pillar made?
Ans: It was made about 1500 years ago.

2. Mention the most striking feature of the Iron Pillar.
Ans: The Pillar has not rusted in all these years.

3. What do you mean by the word ‘Stupa’? [V. Imp.]
Ans: The word Stupa means a mound. It is a Buddhist religious building.

4. Why did devotees walk around the stupa in a clockwise direction?
Ans: They did so to show their devotion.

5. Why was Amaravati famous?
Ans: Amaravati was a place where a magnificent stupa once existed.

6. Marne the deities worshipped in the earliest Hindu temples.
Ans: Vishnu, Shiva, and Durga.

 7. What was the garbhagriha?
Ans: It was a room in the temple during this period.

8. Why was the garbhagriha so important? [V. Imp.]
Ans: The image of the chief deity was placed in the garbhagriha. Also, the priests performed religious rituals here.

9. What was the shikhara?
Ans:It was a tower built on the top of the garbhagriha to mark this out as a sacred place.

 10. What do you know about the monolithic temples at Mahabalipuram?
Ans: Each of these temples was carved out of a huge, single piece of stone.

VI. SHORT ANSWER TYPE QUESTIONS

1. Write a few lines on the Iron Pillar located at Mehrauli, Delhi
Ans: 

• The Iron Pillar located at Mehrauli, Delhi was made about 1500 years ago.
• It is made of iron. Its height is 7.2 m and its weight is over 3 tones.
• It was probably built during the Gupta dynasty.
• It is amazing that the pillar has not rusted in all these years.
• The pillar is a remarkable example of the skill of Indian craftspeople.
• The pillar is famous all over the world.

2. How were stupas and temples built? 
Ans: Building stupas and temples was not an ordinary job. It needed huge wealth which only kings or queens could afford. There were several stages in building a stupa or a temple. Firstly, the good quality stone had to be found, quarried, and transported to the place that was often carefully selected for the new building. Secondly, these rough blocks of stone had to be shaped and covered into pillars, and panels for walls, floors, and ceilings. Thirdly, these had to be placed in precisely the right position. Kings and queens spend money from their treasury to pay the craftspersons.

3. What are the main features of Ajanta paintings?                                                   
Ans: 

• The paintings of Ajanta are world-famous. Ajanta is a place where several caves were hollowed out of the hills over centuries.
• Most of these were Buddhist monasteries while some of them were decorated with paintings.
• The caves are dark inside and therefore most of these paintings were done in the light of torches.
• The colours are vivid even after 1500 years.
• These colours were made of plants and minerals.

CLASS-9 SUBJECT SCIENCE CHAPTER-11 WORK POWER AND ENERGY

 EVENTS CONVENT HIGH SCHOOL

16/12/2021      CLASS- 9   SESSION 2021-22
SUBJECT :SCIENCE 

CHAPTER-11
WORK POWER AND ENERGY

______________________________________

Question 1.
When a body falls freely towards the earth, then its total energy
(a) increases
(b) decreases
(c) remains constant
(d) first increases and then decreases

Answer

Answer: (c) remains constant

---

Question 2.
A car is accelerated on a levelled road and attains a velocity 4 times of its initial velocity. In this process the potential energy of the car
(a) does not change
(b) becomes twice to that of initial
(c) becomes 4 times that of initial
(d) becomes 16 times that of initial

Answer

Answer: (a) does not change

---

Question 3.
In case of negative work the angle between the force and displacement is (NCERT Exemplar)
(a) 0°
(b) 45°
(c) 90°
(d) 180°

Answer

Answer: (d) 180°

---

Kinetic Energy Calculator is a handy tool that solves the kinetic energy problems easily & quickly.

Question 4.
An iron sphere of mass 10 kg has the same diameter as an aluminium sphere of mass is 3.5 kg. Both spheres are dropped simultaneously from a tower. When they are lo m above the ground, they have the same.
(a) acceleration
(b) momenta
(c) potential energy
(d) kinetic energy

Answer

Answer: (a) acceleration

---

Question 5.
A girl is carrying a school bag of 3 kg mass on her back and moves 200 m on a levelled road. The work done against the gravitational force will be (g = 10 ms²)
(a) 6 × 10³ J
(b) 6 J
(c) 0.6 J
(d) zero

Answer

Answer: (d) zero

---

Question 6.
Which one of the following is not the unit of energy?
(a) joule
(b) newton metre
(c) kilowatt
(d) kilowatt hour

Answer

Answer: (c) kilowatt

---

Question 7.
The work done on an object does not depend upon the
(a) displacement
(b) force applied
(c) angle between force and displacement
(d) initial velocity of the object

Answer

Answer: (d) initial velocity of the object

---

Question 8.
Water stored in a dam possesses
(a) no energy
(b) electrical energy
(c) kinetic energy
(d) potential energy

Answer

Answer: (d) potential energy

---

Question 9.
A body is falling from a height h. After it has fallen a height h2, it will possess
(a) only potential energy
(b) only kinetic energy
(c) half potential and half kinetic energy
(d) more kinetic and less potential energy

Answer

Answer: (c) half potential and half kinetic energy

---

Question 10.
The number of joules contained in 1 kWh is
(a) 36 × 105 J
(b) 3.6 × 107 J
(c) 36 × 108 J
(d) 3.7 × 107 J

Answer

Answer: (a) 36 × 105 J

---

Fill in the blanks

1. Work done is product of ………….. and distance moved the direction of the force.

Answer

Answer: force

---

2. If the angle between force and displacement is …………. then work done is said to be zero.

Answer

Answer: 90°

---

3. Energy of a body is defined as the capacity or …………. to do work.

Answer

Answer: ability

---

4. Mechanical energy includes ………….. and ……………

Answer

Answer: kinetic energy, potential energy

---

5. Energy can neither be ………….. nor ………….. it can only transformed from one form to another.

Answer

Answer: created, destroyed

---

6. ………….. is defined as the rate of doing work.

Answer

Answer: Power

---

7. Commercial unit of energy is ………………

Answer

Answer: kilowatt hour

Page 149
Q1. When do we say that work is done?
Work is said to be done when a force causes displacement of an object in the direction of applied force.
Q2. Write an expression for the work done when a force is acting on an object in the direction of its displacement.
Work done = Force x Displacement
Q3. Define 1J of work.
When a force of IN causes a displacement of 1m, in its own direction the work done is said to be one joule.
Q4. A pair of bullocks exerts a force of 140 N on a plough. The field being ploughed is 15 m long. How much work is done in ploughing the length of the field?
Work done = Force x Displacement = 140 x 15 = 2,100 J

Page 156

Q1. What is power?
Power is defined as the rate of doing work
Q2. Define 1 watt of power.
When a work of 1 joule is done in 1 s, the power is said to be one watt.
Q3. A lamp consumes 1000 J of electrical energy in 10 s. What is its power?
Given W = 1000J, t = 10s, P =?
We know, P = W/t = 1000/10 = 100W
Q4. Define average power.
When a machine or person does different amounts of work or uses energy in different intervals of time, the ratio between the total work or energy consumed to the total time is average power.

Q5. A mass of 10 kg is at a point A on a table. It is moved to a point B. If the line joining A and B is horizontal, what is the work done on the object by the gravitational force? Explain your answer.
The work done is zero. This is because the gravitational force and displacement are perpendicular to each other.

Q6. The potential energy of a freely falling object decreases progressively. Does this violate the law of conservation of energy? Why?
It does not violate the law Of conservation of energy. Whatever, is the decrease in PE due to loss of height, same is the increase in the KE due to increase in velocity of the body.

Q7. What are the various energy transformations that occur when you are riding a bicycle?
The chemical energy of the food changes into heat and then to muscular energy. On paddling, the muscular energy changes into mechanical energy

Q8. Does the transfer of energy take place when you push a huge rock with all your might and fail to move it? Where is the energy you spend going?
Energy transfer does not take place as no displacement takes place in the direction of applied force. The energy spent is used to overcome inertia of rest of the rock.

Match the following columns

Column A	Column B
(a) SI unit of power	(i) 1/2 mv2
(b) Kinetic energy	(ii) The change of one form of energy into another
(c) Potential energy	(iii) watt
(d) SI unit of work	(iv) If applied force on an object and displacement is in opposite direction.
(e) Negative work	(v) Energy possessed by a body due to its position or configuration.
(f) Power	(vi) Joule
(g) Expression of kinetic energy	(vii) Energy possessed by a body due to its motion.
(h) Transformation of energy	(viii) Rate of doing work

Answer

Column A	Column B
(a) SI unit of power	(iii) watt
(b) Kinetic energy	(vii) Energy possessed by a body due to its motion.
(c) Potential energy	(v) Energy possessed by a body due to its position or configuration.
(d) SI unit of work	(vi) Joule
(e) Negative work	(iv) If applied force on an object and displacement is in opposite direction.
(f) Power	(viii) Rate of doing work
(g) Expression of kinetic energy	(i) 1/2 mv2
(h) Transformation of energy	(ii) The change of one form of energy into another