CLASS-9 SUBJECT SCIENCE CHAPTER-4 STRUCTURE OF THE ATOMS (ENGLISH MEDIUM)

 EVENTS CONVENT HIGH SCHOOL

08/01/2022      CLASS- 9   SESSION 2021-22
SUBJECT :SCIENCE 

CHAPTER-4
STRUCTURE OF ATOM

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Textbook  – Page 47
Question 1. What are canal rays?
Answer: Canal rays are positively charged radiations which led to the discovery of positively charged sub-atomic particle called proton.

Question 2. If an atom contains one electron and one proton, will it carry any charge or not?
Answer: The atom will be electrically neutral as one – ve charge balances one + ve charge.

Textbook – Page 49
Question 1. On the basis of Thomson’s model of an atom, explain how the atom is neutral as a whole.
Answer: According to Thomson’s model of an atom
(i) An atom consists of a positively charged sphere and the electrons are embedded in it,
(ii) The negative and positive charges are equal in magnitude. So the atom is electrically neutral.

Question 2. On the basis of Rutherford’s model of an atom, which sub-atomic particle is present in the nucleus of an atom?
Answer: As per Rutherford’s model of an atom, the protons which are positively charged are present in the nucleus of an atom.

Question 3. Draw a sketch of Bohr’s model of an atom with three shells.
Answer:

Question 4. What do you think would be the observation if the a-particle scattering experiment is carried out using a foil of a metal other than gold?
Answer: On using any metal foil, the observations of the a-particle scattering experiment would remain the same as all atoms would have same structure.

Textbook – Page 49
Question 1. Name the three sub-atomic particles of an atom.
Answer: The sub-atomic particles of an atom are

Question 2. Helium atom has an atomic mass of 4 u and two protons in its nucleus. How many neutrons does it have?
Answer:

Textbook  – Page 50
Question 1. Write the distribution of electrons in carbon and sodium atoms.
Answer:

Question 2. If K and L shells of an atom are full, then what would be the total number of electrons in the atom?
Answer: K shell can hold 2 electrons and L shell can hold 8 electrons.When both the shells are full, there will be (8 + 2) 10 electrons in the atom.

Text Book

Question 1. Compare the properties of electrons, protons and neutrons.
Answer:

Question 2. What are the limitations of J.J. Thomson’s model of the atom?
Answer: According to J.J. Thomson’s model of an atom, the electrons are embedded all over in the positively charged spheres. But experiments done by other scientists showed that protons are present only in the centre of the atom and electrons are distributed around it.

Question 3. What are the limitations of Rutherford’s model of the atom?
Answer: According to Rutherford’s model of an atom the electrons are revolving in a circular orbit around the nucleus. Any such particle that revolves would undergo acceleration and radiate energy. The revolving electron would lose its energy and finally fall into the nucleus, the atom would be highly unstable. But we know that atoms are quite stable.

Question 4. Describe Bohr’s model of the atom.
Answer: Bohr’s model of the atom
(1) Atom has nucleus in the centre.
(2) Electrons revolve around the nucleus.
(3) Certain special orbits known as discrete orbits of electrons are allowed inside the atom.
(4) While revolving in discrete orbits the electrons do not radiate energy.
(5) These orbits or shells are called energy levels.
(6) These orbits or shells are represented by the letters K, L, M, N or the numbers n = 1, 2, 3, 4

Question 5. Compare all the proposed Bohr’s models of an atom given in this chapter.
Answer:

Question 6. For the following statements, write T for True and F for False.
(a) J.J. Thomson proposed that the nucleus of an atom contains only nucleons.
(b) A neutron is formed by an electron and a proton combining together. Therefore,it is neutral.
(c) The mass of an electron is about 1/2000 times that of proton.
(d) An isotope of iodine is used for making tincture iodine, which is used as a medicine.
Answer: (a) False (b) False
(c) True (d) False

 
Question 7. Rutherford’s alpha-particle scattering experiment was responsible for the discovery of
(a) Atomic nucleus (c) Proton
(b)Electron (d)neutron
Answer: (a) Atomic nucleus

Question 8.Isotopes of an element have
(a) the same physical properties (c) different number of neutrons
(b)different number of neutrons (d) different atomic numbers.
Answer: (c) different number of neutrons

Question 9. Number of valence electrons in Ct ion are :
(a) 16 (b) 8
(c) 17 (d) 18
Answer: (b) 8

Question 10. Which one of the following is a correct electronic configuration of sodium?
(a) 2, 8 (b) 8, 2, 1
(c) 2, 1, 8 (d) 2, 8, 1
Answer: (d) 2, 8, 1

Question 11. Complete the following table.

Answer:

CLASS-6 SUBJECT -SCIENCE CHAPTER-3 FIBER TO FABRIC

  EVENTS CONVENT HIGH SCHOOL

05/01/2022      CLASS- 6   SESSION 2021-22
SUBJECT :SCIENCE 

CHAPTER-3

FIBER TO FABRIC
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Q.1. Classify the following fibres as natural or synthetic: nylon, wool, cotton, silk, polyester, jute.
Ans. Natural fibres: wool, cotton, jute, silk.
Synthetic fibres: nylon, polyester.

Q.2. State whether the following statements are ‘true’ or false’:
(a) Yam is made from fibres.
(b) Spinning is a process of making fibres.
(c) Jute is the outer covering of coconut.
(d) The process of removing seeds from cotton is called ginning.
(d) Weaving of yam makes a piece of fabric.
(e) Silk fibre is obtained from the stem of a plant.
(g) Polyester is a natural fibre.
Ans.
(a) True
(b) False
(c) False
(d) True
(e) True
(f) False
(g) False

Q.3. Fill in the blanks:
(a) Plant fibres are obtained from____________ and___________ .
(b) Animal fibres are___________ and___________ .
Ans.
(a) cotton plants, jute plants
(b) wool, silk

VERY SHORT ANSWER TYPE QUESTIONS

Q.1. Name two varieties of cloth materials which are commonly used.
Ans. Cotton, silk/wool.

Q.2. What are fabrics?
Ans. Fabrics mean a woven material, textile or other materials resembling woven cloth.

Q.3. Name some fabrics in your surroundings.
Ans. Bed-sheets, blankets, curtains, table clothes, towels and dusters.

Q. 4.  Name the thing which is used to make fabric.
Ans. Yarns.

Q.5. What are yarns made of?
Ans. Yarns are made up of thin strands called fibres.

Q.6. How many types of fibres are there?                                                        ,
Ans. There are two types of fibres:
(i) Natural fibres
(ii) Synthetic fibres

SHORT ANSWER TYPE QUESTIONS

Q.1. What do you observe when you are visiting a nearby tailoring shop?
Ans. In a tailoring shop we observe that there are many cuttings of fabrics left over after stitching. We see that some cuttings are of cotton, some are of silk or wool and some are of synthetic fibres.

Q.2. List the steps involved in the preparation of fabric.
Ans. The following steps are involved in the preparation of fabrics:
(i) Obtaining fibre,
(ii) Preparation of yarn from fibres by spinning,
(iii) When two sets of yarn are involved, yarns are woven on looms to make a fabric. When a single yam is used, the fabric is prepared by knitting.

Q.3. What are natural fibres? Explain with examples.
Ans. The fibres obtained from plants and animals are called natural fibres. For example, cotton from cotton bolls, jute from jute plant, silk from cocoon of silkworm and wool from hair of animals like sheep or goat.

Q.4. What are synthetic fibres?
Ans. The fibres which are made from chemical substances or which are not obtained from the plant and animal sources are called synthetic fibres. For example, polyester, nylon, and acrylic, etc.

Q.5. Explain how jute is obtained from the jute plant.
Ans. The jute plant is normally harvested at flowering stage. The stems of harvested plants are bundled and immersed in water for 10 to 15 days. The stems rot (the process is called retting) and fibres are separated by hand. These fibres are converted into yarns to make fabrics (Fig. 3.10).

Q. 6. What are looms?
Ans. The devices on which weaving of fabrics takes place are called looms. The looms are either hand operated or power operated.

LONG ANSWER TYPE QUESTIONS

Q.1. Describe the process of the formation of yam from cotton wool.
Ans. The cotton wool is obtained from cotton plants. The cotton plants are grown in fields. They are usually grown at the places having black soil and warm climate. The fmits of the cotton plants called cotton bolls are about the size of lemons. After maturing, the bolls burst open and seeds covered with cotton fibres can b,e seen. From the cotton bolls cotton is picked by hands. Fibres are then separated from the seeds by combing. This process is called ginning of cotton. It is done by hand or by machines. These fibres are then converted into yam.

Q.2. Describe the process of spinning and weaving.
Ans. Spinning: The process of making yarn from fibres is called spinning. In this process fibres from a mass of cotton wool are drawn out and twisted. By this fibres come together to form a yarn. Spinning can be done by hand, by takli and charkha. On a large scale, spinning is done with the help of machines.
Weaving: The process of arranging two sets of yarns together t6 make a fabric is called weaving. The process of weaving can be done on looms. The looms are either-hand operated or power operated.

CLASS-8 SOCIAL SCIENCE HISTORY CHAPTER-8 INDIA AFTER INDEPENDENCE

 EVENTS CONVENT HIGH SCHOOL

05/01/2022      CLASS- 8   SESSION 2021-22
SUBJECT :SOCIAL STUDIES 

CHAPTER-8 HISTORY

INDIA  AFTER INDEPENDENCE
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Question 1.Choose the correct option.
(i) Which one is not a feature of the Indian Constitution?
(a) It adopted the universal adult franchise
(b) It gave politicians special powers
(c) It provided equality before the law to all citizens
(d) It offered special privileges for the poorest and most disadvantaged Indians

(ii) Which one is the subject of the State List?
(a) Education
(b) Defence
(c) Forests
(d) Agriculture

(iii) Who is called the father of the Indian Constitution?
(a) Mahatma Gandhi
(b) Jawaharlal Nehru
(c) Vallabhbhai Patel
(d) Bhimrao Ambedkar

(iv) The bilingual state of Bombay was divided into separate states for
(a) Marathi and Telugu speakers
(b) Marathi and Malayalam speakers
(c) Marathi and Gujarati speakers
(d) Bengali and Gujarati speakers

(v) Who was the Deputy Prime Minister of Independent India?
(a) Motilal Nehru
(b) Bhim Rao Ambedkar
(c) Vallabhbhai Patel
(d) MaulanaAzad
Answer.
(i) (b), (ii) (a), (iii) (d), (iv) (d), (v) (c).

Question 2.Fill in the blanks with appropriate words to complete each sentence.

1. Prime Minister Jawaharlal Nehru was also the ………….. minister of newly independent India.
2. The Bhilai steel plant was set up with the help of the former …………. in 1959.
3. In 1966, the state of Punjab was divided into ………… and ……………..
4. India’s population in 1947 was almost …………… million.
5. Soon after Independence, India chose to grant …………… right to all its citizens regardless of gender, class or education.

Answer.

1. Foreign
2. Uncivilised, civilised
3. Punjab, Haryana
4. 345
5. Voting

Question 3.State whether each of the following statements is True or False.

1. The Adivasis or the Scheduled Tribes were not granted reservation in seats and jobs.
2. Dr. B.R. Ambedkar belonged to a Marathi-speaking Dalit family.
3. Bridges and dams became the symbol of development in free India.
4. Dharavi in Gujarat is one of the world’s largest slums.
5. Nehru and Patel wanted to divide the country on the basis of language.

Answer.

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

Question 4.
Match the items given in Column A correctly with those given in Column B.

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

Very Short Answer Type Questions

Question 1.When was the Indian Constitution adopted?
Answer.
The Indian Constitution was adopted on 26 January 1950.

Question 2.Which step has been described as revolutionary?
Answer.
All Indians above the age of 21 would be allowed to vote in state and national elections.

Question 3On what point did Nathuram Godse disagree with Gandhiji?
Answer.
Nathuram Godse disagreed with Gandhiji’s conviction that Hindus and Muslims should live together in harmony.

Question 4.Name two subjects of the State List.
Answer.
Education and health.

Question 5.Name two subjects of the Concurrent List.
Answer.
Forests and agriculture.

Short Answer Type Questions

Question 1.What created problems in unifying the people of India after it got independence?
Answer.
The points that created problems were:

1. At the time of independence, India’s population was large. It was divided too. There were divisions between high castes and low castes, between the majority Hindu community and Indians who practised other faiths.
2. The citizen of this country spoke different languages, wore different kinds of dresses, ate different kinds of foods, and practiced different professions.

Question 2.What was the label of development of India at the time it got inde¬pendence?
Answer.
At the time India got independence the label of its development was very low. A vast majority of Indians lived in the villages. Farmers and peasants depended on the monsoon for their survival. So did the non-farm sector of the rural economy, for if the crops failed, barbers, carpenters, weavers, and other service groups would not get paid for their services either. In the cities too the condition was not good. Factory workers usually lived in crowded slums. They had little access to education and health care.

Question 3.What special privileges were offered for the poorest and most disadvantaged Indians by the constitution?
Answer.
First of all the practice of untouchability was abolished. Hindu temples were thrown open to all including the former untouchables.

• A certain percentage of seats in legislatures as well as jobs in government were reserved for members of the lowest castes.

Long Answer Type Questions

Question 1.Give detailed descriptions of the features of the Indian Constitution.
Answer.
We have a written Constitution which was adopted on 26 January 1950.
Features:
(a) One feature of the Indian Constitution was that it adopted a universal adult franchise. All Indians above the age of 21 (now 18) would be allowed to vote in state and national elections.

(b) Our Constitution guaranteed equality before the law to all citizens, regardless of their caste or religious affiliation.

(c) The Constitution offered special privileges for the poorest and most disadvantaged Indians. The evil practice of untouchability was abolished. Hindu temples were thrown open to all, including the former untouchables. After a long debate, the Constituent Assembly also recommended that a certain percentage of seats in legislatures as well as jobs in government be reserved for members of the lowest castes, including the Adivasis.

Question 2.Give an account of the successes and failures of the country during the sixty-two years of its independence.
Answer.
Sixty-two years of independence have passed. This duration covers a long journey. A lot has been achieved during this time. But at the same time, there have been a number of failures.

Successes :

1. India is still united and it is still democratic. These achievements definitely make us proud. Many foreign observers had felt that India could not survive as a single country. Others believed that it would come under military rule. Neither of these predictions proved to be true. As many as thirteen general elections have been held since independence, as well as hundreds of state and local elections.
2. There is a free press and an independent judicially.
3. The fact that people speak different languages or practice different faiths has not come in the way of national unity.

Failures:

1. Deep divisions are still there. Despite constitutional guarantees, people belonging to the lowest castes, such as Dalits face violence and discrimination. In many parts of rural India, they are not allowed access to water sources, temples, parks, and other public places.
2. The gulf between the rich and the poor has grown over the years. Some groups of people avail all facilities while many others continue to live below the poverty line.
3. Our Constitution provides equality before the law but in real life, this does not happen. Some Indians are more equal than others.