RBSE Solutions for Class 8 Science Chapter 12 Artificial Satellite

Rajasthan Board RBSE Class 8 Science Chapter 12 Artificial Satellite Current

RBSE Solutions for Class 8 Science

RBSE Solutions for Class 8 Science Chapter 12 Artificial Satellite

RBSE Class 8 Science Artificial Satellite Intext Questions and Answers

Page No 133.

Question 1.
How do we get the signals on radio, television, mobiles etc. through the satellites?
Answer:
Through micro radio waves, signals are received on ir TN., mobile, radio etc. by satellite.

Question 2.
Discuss among each other and tell how ¡s communication arrangement taking place through artificial satellite.
Answer:
Take an example of live telecast of any game on TN., its communication system is in following way –
RBSE Solutions for Class 8 Science Chapter 12 Artificial Satellite-1

RBSE Class 8 Science Artificial Satellite Text book Questions and Answers

Choose the correct answers:

Question 1.
If any object is thrown upwards with velocity more than 11.2 km/sec, then the object will –
(a) Return to Earth
(b) Revolve around the Earth
(c) went into space
(d) None of the above
Answer:
(c) went into space

Question 2.
The name of the first Indian artificial satellite launched in space is –
(a) Bhaskar-1
(b) Aryabhalt
(c) Kalpana-1
(d) INSAT-1
Answer:
(b) Aryabhalt

RBSE Solutions for Class 8 Science Chapter 12 Artificial Satellite

Question 3.
The satellite is used for communication is called –
(a) Polar satellite
(b) SLV
(c) Geo-stationary satellite
(d) IRS-1
Answer:
(c) Geo-stationary satellite

Fill in the blanks with suitable words:

  1. The minimum velocity by which an object thrown upwards it crosses the gravitational attraction of earth is called as ……………………….
  2. Geo-stationary satellite revolves ………………………. orbits of earth.
  3. The first Indian artificial satellite ………………………. was launched in April 19, 1975.

Answer:

  1. Escape velocity
  2. equatorial
  3. Aryabhata

Short Answer Questions:

Question 1.
Explain the difference between the artificial satellites and natural satelllte
Answer:
Natural objects revolving around the planets are called natural satellite.
Example:
Earth’s natural satellite is Moon. Man made objects which revolve around the Earth and other planets in particular orbits are called artificial satellites. Example : IRS series satellites.

RBSE Solutions for Class 8 Science Chapter 12 Artificial Satellite

Question 2.
The objects, which are thrown upwards from earth, return back to earth whereas artificial satellites does not return back. Why?
Answer:
Objects when thrown upwards from Earth come hack to earth because Earth’s gravitational force works on them. Whereas artificial satellites are launched with a velocity slightly lesser than escape velocity hence earth’s gravitational force is almost on them. Due to this they do not return back to the Earth and move around the earth in fixed orbits.

Question 3.
Differentiate between geo-stationary satellite and polar satellite on the basis of orbital motion, distance from earth and its uses.
Answer:
RBSE Solutions for Class 8 Science Chapter 12 Artificial Satellite-2

Long answer Questions:

Question 1.
What do you mean by artificial satellite? Write its uses.
Answer:
Artificial Satellites – Man made objects which revolve around tile Earth and other planets in particular orbits arc called artificial satellites.

Uses of Artificial Satellites –

  1. An artificial satellite receives signals from equipment placed on any part of earth and then sends them to different places of earth. Different means of telecommunication like telephone, mobile, television, internet work on this principle.
  2. It is useful in gathering information regarding weather and geology.
  3. In making estimates of area and production of crops.
  4. Alerts regarding flood and droughts and estimation of damages caused by them.
  5. Search of estimation underground water and management of water resources.
  6. Locating the mineral resources in the Earth.
  7. Survey of the forests and helping in efforts of environment conservation.
  8. Surveillance of airports, seaports and army stations for managing their safety. stations for managing their safety.
  9. Spying military operations.
  10. Collecting information regarding the happening space and universe.
  11. Locating the exact position of airplane, ships, person or an object.

Question 2.
Write down any five Indian satellite’s names, launching year and their uses.
(OR)
Make a list of artificial satellite projected by India, with their uses.
Answer:
RBSE Solutions for Class 8 Science Chapter 12 Artificial Satellite-3

Question 3.
Describe the various types of artificial satellites.
Answer:
Types of Artificial Satellites:
Depending upon the distance from the Earth surface and the uses, artificial satellites are divided broadly into two categories.

1. Gee-Stationary Satellite:
Those satellites which when seen from at particular place appears motionless at a fixed position in the sky are known as geo-stationary satellites. These satellites are placed at a height of 36000 km from the surface of earth. These satellites revolve at the equatorial orbit. Geo-stationary satellites arc used for television, telephone, satellite radio and other India of global communication. Hence, they are also known as communication satellite.

2. Polar Satellite –
These are satellites which revolves in polar orbit around the earth. They are at a height of 500 to 800 kilometer from the earth’s surface, The polar satellites are used to get important information like the cloud images. atmospheric data, detection of ozone whole. Information received from polar satellites are helpful for remote sensing, meteorological science and environmental studies.

RBSE Solutions for Class 8 Science Chapter 12 Artificial Satellite

Question 4.
Write an essay on contribution of Indian space research organisation in Indian space programme.
Answer:
Indian National Committee for Space Research (INCOSPAR) was formed by Atomic Energy Department in 1962 under the leadership of famous Indian scientist Homi Jehangir Bhabha. This name was reformed as Indian Space Research Organisation (ISRO) in 1969. Manufacturing of Indian artificial satellite, development and launching of satellite are by ISRO.

With the help of the experiments based on space by ISRO, many research and development works are performed on space and planets. Dr. A.P.J. Abdul Kalam played a major role in manufacturing of launching vehicle by working on important projects of ISRO. ISRO lias launched more than 50 foreign satellites in space ISRO has so many centers in India. Its main launching station is in Shrihankota (Andhra Pradesh). Recently, in February 2017, ISRO has setted a new world record by launching 104 artificial satellite together into the space.

RBSE Class 8 Science Artificial Satellite Important Questions and Answers

Objective Questions:

Question 1.
India has made many missiles. Who is called the ‘missile man’?
(a) Kalpana Chawla
(b) Dr. Vikrarn Sarahhai
(c) Dr. A.P.J. Abdul Kalain
(d) Aaryahhatt
Answer:
(c) Dr. A.P.J. Abdul Kalain

Question 2.
Manufacturing launching etc. of artificial satellites in India ¡s done where?
(a) INCOSPAR
(b) ISRO
(c) Remote sensing
(d) None of these
Answer:
(b) ISRO

RBSE Solutions for Class 8 Science Chapter 12 Artificial Satellite

Question 3.
When was the first artificial satellite of the world launched ?
(a) 4 October, 1957
(b) 19 April, 1975
(c) 5 September, 1979
(d) 31 October, 1980
Answer:
(a) 4 October, 1957

Question 4.
The first artificial satellites launched by India in the year –
(a) 4 October, 1957
(b) 19 April. 1975
(c) 5 October, 1975
(d) 30 April, 1975
Answer:
(b) 19 April. 1975

Question 5.
The artificial satellite launched by India only for education is –
(a) EDUSAT
(b) KALPANA-I
(c) INSAT
(d) BHASKAR-I
Answer:
(a) EDUSAT

Question 6.
The main launching centre of ISKO is situated at –
(a) Jodhpur
(b) Sriharikota
(c) Ahemdabad
(d) Tripura
Answer:
(b) Sriharikota

RBSE Solutions for Class 8 Science Chapter 12 Artificial Satellite

Question 7.
Number of planets in our solar system –
(a) 1
(b) 9
(c) 4
(d) 8
Answer:
(d) 8

Question 8.
Revolving time taken by Geo stationary satellite is –
(a) 6 hours
(b) 24 hours
(c) 48 hours
(d) 72 hours
Answer:
(b) 24 hours

Question 9.
First Indian women space traveller was –
(a) Kalpana Chawla
(b) Bachendri Pal
(c) Sarojini Naidu
(d) Indira Gandhi
Answer:
(a) Kalpana Chawla

Question 10.
Kaipana-I artificial satellite is related to –
(a) Education
(b) Communication
(c) Remote Sensing
(d) Weather Science
Answer:
(d) Weather Science

RBSE Solutions for Class 8 Science Chapter 12 Artificial Satellite

Fill in the blanks:

  1. Every satellite revolves around the earth in ……………………….. (fixed orbit/unfixed orbit)
  2. Geo stationary satellites are also called ……………………….. (weather satellite communication satellite)
  3. Microwaves and radio waves can pass through ……………………….. also. (medium/without. medium)
  4. First Indian satellite is ……………………….. (Bhaskar/Aryabhata)
  5. Artificial satellites are launched with the help of various ……………………….. (space shuttles/space car)
  6. Man made satellites are called ……………………….. satellites. (artificial/natural)
  7. Polar satellites revolves around the earth in ……………………….. (Polar orbits/Non-polar orbits)
  8. Satellite launched for only education purpose is ……………………….. (EDUSAT/INSAI)

Answer:

  1. fixed orbit
  2. communication satellite
  3. without medium
  4. Aryabhata
  5. space shuttles
  6. artificial
  7. Polar orbit
  8. EDUSAT

RBSE Solutions for Class 8 Science Chapter 12 Artificial Satellite

State True or False:

  1. Proper communication system on earth is possible because of natural satellites.( )
  2. Polar satellites revolve at a less height from the surface of earth. ( )
  3. Radio waves can travel through vaccum also. ( )
  4. Artificial satellites helps to find out mineral resources in the earth crust. ( )
  5. The main launching station of ISRO is in Ahemdahad. ( )
  6. Vikram Sarabhai Space Centre is at Trivantpuram. ( )
  7. EDUSAT satellite is launched for remote sensing. ( )
  8. For earth the ascape velocity is 11.2 km/sec. ( )

Answer:

  1. False
  2. True
  3. True
  4. True
  5. False
  6. True
  7. False
  8. True.

Match the Column –

Question 1.
Match the following correctly:
RBSE Solutions for Class 8 Science Chapter 12 Artificial Satellite-4
Answer:

  1. (b)
  2. (a)
  3. (d)
  4. (e)
  5. (c)

Very Short Answer Type Questions:

Question 1.
Artificial satellite is also used to find out under ground minerals. Write two uses of the INSAT satellite.
Answer:
Two uses of INSAT satellite are as follows –

  1. In telecommunication system
  2. Weather forecasting.

Question 2.
What is artificial satellite ?
(OR)
What do you understand with artificial satellite? How many types of these are? Write the names.
Answer:
Man made bodies which are revolving around the earth or any other planets are called as artificial satellites.
Artificial satellites are of two types –

  1. Geo-stationary satellite
  2. Polar satellites.

Question 3.
What are natural satellites ?
Answer:
Natural objects revolving around all the planets of solar system are called natural satellite.

RBSE Solutions for Class 8 Science Chapter 12 Artificial Satellite

Question 4.
Name the natural satellite earth.
Answer:
‘Moon” is the natural satellite of earth.

Question 5.
Name some artificial satellites.
Answer:
Aryabhatt, Bhaskar, satellites of INSAT series, Polar satellite, Kalpana, EDUSAT etc.

Question 6.
State some uses of artificial satellites.
Answer:
Artificial, satellites are useful in

  1. telecommunication system
  2. weather related information and warning
  3. in scientific research
  4. underground water study and to find out minerals from earth
  5. in surveying of forests
  6. in surveying of atmosphere
  7. as detective
  8. to find location of any vehicle and mobile phone.

Question 7.
What is gravitational force?
Answer:
The force of attraction with which the earth attracts all the object towards itself is called gravitational force.

Question 8.
What is meant by escape velocity’?
Answer:
The minimum velocity, by which any body projected upward and crossed the gravitation of earth is called as ‘escape velocity’.

RBSE Solutions for Class 8 Science Chapter 12 Artificial Satellite

Question 9.
What is the escape velocity for the Earth?
Answer:
11.2 kilometer per second.

Question 10.
What is meant by Geo-stationary satellite?
Answer:
Geo-Stationary Satellite:
Those satellites which when seen from a particular place of the Earth appear motionless at a fixed position in the sky.

Question 11.
In which orbit Geo-stationary satellites revolve?
Answer:
in equator orbit.

Question 12.
What is the time period of revolution of the geo-stationary satellite ?
Answer:
It is equal to the time period of rotation of the earth i.e. 24 hours.

Question 13.
In which orbit polar-satellites revolve?
Answer:
Polar satellites revolves in the polar orbit of the earth.

Question 14.
Write the names of three remote sensing satellites launched by India.
Answer:
IRS-1A, IRS-2B, IRS-3C.

RBSE Solutions for Class 8 Science Chapter 12 Artificial Satellite

Question 15.
Which country and when has launched the first artificial satellite in the world?
Answer:
The first artificial satellite in the world was launched by Russia on 4th October, 1957.

Question 16.
Name the main satellite launched by India with the help of ISRO.
Answer:
Aryabhatt, Bhaskar-I, satellites of INSAT series, R emote sensing satellites. Kalpana-I. EDUSAT etc.

Question 17.
Write the name and launching year of satellite launched for equcation.
Answer:
EDUSAT (Launching year-2004).

Question 18.
Name the artificial satellites launched by India for the information about weather forecasting only.
Answer:
For this Kapana-I was launched in year 2002.

Question 19.
From where does the artificial satellite Aryabhatt was launched.
Answer:
The first artificial satellite of India Aryahhatt was launched from the space centre of Soviet Union on 19th April. 1975.

Question 20.
In which city of Rajasthan is situated the remote sensing centre ? What is its work?
Answer:
There is a Remote Sensing Centre situated at Jodhpur city in Rajasthan for study of images. data and information received from artificial satellites.

Question 21.
What is the use of satellites of INSAT series ?
Answer:
These satellites are used for forecasting weather and tele-communications.

RBSE Solutions for Class 8 Science Chapter 12 Artificial Satellite

Question 22.
What would happen if any object ¡s thrown with a velocity higher than escape velocity ?
Answer:
Object will go in space forever.

Question 23.
Why is geo-stationary satellite also called communication satellite ?
Answer:
Geo-stationary satellites are used for satellite telephones, satellite television, satellite radio and other global media of communication. Hence, they are also called communication satellites.

Short Answer Type Questions:

Question 1.
Write a short note On India’s first artificial satellite.
Answer:
India’s first artificial satellite was ‘Aryabhata’. This was named after the famous Indian scientist mathematician Aryabhata. It was launched on 19 April. 1975 from Bekanoor Space Centre. Soviet Union (Russia). Its main work was to study Earth’s atmosphere.

Question 2.
What is the prerequisite for launching artificial satellite ?
Answer:
The prerequisite for launching artificial satellite is that its velocity should be slightly lesser than escape velocity (11.2 kilometer per second). An artificial satellite is launched with the help of rocket or launching vehicle.

Question 3.
Why do objects thrown upwards with less velocity come hack towards Earth ?
Answer:
Due to Earth gravitational force as the velocity of the objects Thrown upwards is very less or negligible in comparison lo the earth’s escape velocity.

Question 4.
What is meant by escape velocity ? What is the escape velocity of any object on earth?
Answer:
Minimum velocity with which the body has to he projected vertically upwards from the surface of the earth SO that it just crosses the gravitational held of the earth and never returns on its own is called as escape velocity for earth. The value of escape velocity is 11 .2 kilometers per second.

Question 5.
Why does geo-stationary satellite appear stationary when seen from Earth ? Draw its figure also.
Answer:
The revolving time of geo-slationary satellite is equal to the rotation rime of Earth. Therefore, a geo-stationary satellite also takes 24 hours to complete one revolution around the earth from West East. Hence, when seen from Earth appears stationary.
RBSE Solutions for Class 8 Science Chapter 12 Artificial Satellite-5

Question 6.
Why geo-stationary satellites are called communication satellites ?
Answer:
Geo-stationary satellites are used for global communication in satellite telephone, satellite television, satellite radio etc. Thus geo-stationary satellite are called as communication satellite.

Question 7.
Explain in brief about ISRO.
Answer:
ISRO is formed in the year 1969, manufacturing of Indian artificial satellite, development and launching of satellite are done by ISRO. With the help of the experiments based on space by ISRO. many research and development works are performed on space and planets. Dr. A.PJ. Abdul Kalain played a major role in manufacturing of launching vehicle by working on important projects of ISRO. Today India is self dependent in manufacturing of high level satellite launching vehicles, such that America and other countries are also using Indian launching vehicles for artificial satellite launching. ISRO has launched more than 50 foreign satellites in space. ISRO has so many centers in India, Its main launching station is in Shriharikota (Andhra Pradesh).

Question 8.
What information is provided by polar satellites and how are they useful ?
Answer:
Polar satellites provide Information and pictures regarding clouds, atmosphere, hole in the ozone layer, etc. Information provided by polar satellites is used in remote sensing, weather science and environment studies.

Question 9.
How are artificial satellites useful In telecommunications?
Answer:
Artificial satellites collect signals from telephone, mobile, radio, television, internet, etc. and send them to the different places on the Earth.

RBSE Solutions for Class 8 Science Chapter 12 Artificial Satellite

Question 10.
How is artificial satellite useful In agriculture?
Answer:
Artificial satellites re useful In agriculture In the following ways –

  1. Determining the area under and estimation of yield of crops.
  2. Alerts and warmings regarding floods and droughts and determination of damage caused by them.
  3. Search of underground water and water resource management.

Question 11.
How is artificial satellite useful in defence sector ?
Answer:
Following are the uses of artificial satellites in defence sector –

  1. Surveillance of airports. seaports and army stations. so that their safety management is done properly.
  2. Knowing the exact location of airplane. ships, person or object.
  3. Spying foreign military operations.

Question 12.
Write a short note on Indian’s polar satellites.
Answer:
At the end of 1980, India started sending polar satellites to the space. They were known as Indian Remote Sensing Satellites. These satellites are helpful in management of natural resources, data collection. forecasting of weather and experiments related in space.

Question 13.
What are INSAT series satellites ?
Answer:
In the beginning of year 1980’s. INSAT series satellites were launched with the help of European launching vehicle. These satellites are used for forecasting weather and tele- Communication.

Long Answer Type Questions:

Question 1.
How communication process takes place by artificial satellite. Represent it through the diagram.
Answer:
RBSE Solutions for Class 8 Science Chapter 12 Artificial Satellite-6
Step – 1:
According to diagram as recording of cricket game is going on.

Step – 2:
Video recording of the game is sent through elecromagnetic signals on earth station.

Step – 3:
This video recording is sent back to artificial satellites with the help of radio waves or signals from the earth station.

Step-4:
From the satellites the program is resent to the dish antenna through radio waves or signals.

Step – 5:
Through dish antenna the video recording of cricket game is telecasted on the T.V. in the form of images and sound by electromagnetic signals.

Question 2.
Write a short note on famous Indian scientist Dr. Vikram Ambalal Sarabhai.
Answer:
Dr. Vikram Ambalal Sarabhai was born on 12th August, 1919 in Ahmedabad city of Gujarat. He was one of the main scientists of India and in the year 1966 government of India awarded him ‘Padma Bhushan’ award in the field of science and technology. Dr. Vikram Sarahhai made India recognised all over the world in the field of space research. He got doctrate degree in cosmic ray, Physics from Cambridge (England).

He wrote 86 scientific research papers, and established more than 40 centres. Vikram Sarabhai Research Centre, Thiruvanthapuram and Space Application Centre, Ahmedahad are for space research. Dr. Vikram Sarabhai was a scientist, visionary and not only a brilliant industrial manager but he iso had great interest in music, photography, archaeology and fine arts, etc. He died on 30th December, 1971 in Thiruvanthapuram at the age of 52. He was awarded ‘Padma Vibhushan’ posthumously.

RBSE Solutions for Class 8 Science Chapter 12 Artificial Satellite

Question 3.
Write a short note on Dr. A.P.J. Abdul Kalam.
Answer:
Dr. APJ Abdul Kalam was born on 15 October, 1931 in Rameshavaram (Tamil Nadu). He worked as a scientist and as an engineer in many important projects of Defence Research and Development Organisation (DR DO) and Indian Space Research Organisation (ISRO). While working in ISRO. he played a signidcanl role in the development of India’s first indigenous satellite launching vehicle SLy-hi. Because of this in 1980 Rohini Satellite could he established successfully in the orbit close to Earth. Dr. Kalam contributed importantly in India’s missile programme. Hence, he is known as Missile Man’ in India. Dr. Kalarn was also India’s 11th President. He wrote many books apart from teaching. Indian government awarded him with Padma Bhushan and prestigious Padma Vibhushan, Bharat Ratna. etc. He died due to heart attack on 27 July, 2015 in Shillong, Meghalaya.

Question 4.
Write a short note on Kalpana Chawla.
Answer:
She is the first Indian women in space. She died during the returning of space shuttle Columbia on earth. She was born on 17th March, 1962 and dead on 1st February, 2003. Satellite launched for weather purpose information by ISRO on 5th February 2003 was named on first Indian lady astronaut Kalpana Chawala as Kalpana-l. ibis is the first satellite, which is used for metrological science only.

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