CBSE CLASS X Physics

(Space Exploration)

One mark questions with answers

Q1. Define apogee of the orbit of a satellite.

Ans1. Satellites revolve in elliptical orbits around a planet. Apogee is defined as the farthest point on the orbit of a satellite from the planet.

Q2. Define inclination of the orbit of a satellite.

Ans2. Satellites revolve in elliptical orbit around a planet and plane of these orbits is inclined at some angle with the equator of the earth. This angle of the orbit with the equator of the earth is defined as inclination of the orbit.

Q3. What is meant by the statement "Perigee of the orbit of a satellite is 100 km"?

Ans3. This means that the nearest point on the orbit of the satellite is 100 km from the earth or the planet.

Q4. The time taken by an artificial satellite to complete one revolution around the earth is same as the earth takes to complete one rotation about its axis. Name the type of orbit that this satellite has.

Ans4. When the time of revolution of a satellite around the earth is same as time period of one complete rotation of the earth about its own axis then the orbit of satellite is defined as geostationary orbit.


Two mark questions with answers

Q1. Define the characteristics of the orbit of a satellite around the earth.

Ans1. There are three characteristics:
(i) Apogee: It is the point on the orbit of the satellite which is farthest from the earth.
(ii) Perigee: It is the point on the orbit, which is nearest to the earth.
(iii) Inclination: The angle made by the orbit with the equator is called its inclination.

Q2. Name four areas in which space technology finds use and state its applications.

Ans2. Following are the important applications of space science:
(i) Satellite communication,
(ii) Weather monitoring and forecasting,
(iii) Collecting information about other planets and the outer space,
(iv) Study of natural resources from outer space.

Q3. What are geostationary satellites? Give their two applications.

Ans3. Geostationary satellite is the satellite, which appear to be stationary relative to the earth. This is made possible by making the period of revolution of the satellite equal to the period of rotation of the earth about its own axis.
INSAT-1D is India's geostationary satellite in operation.
Application: (i) Satellite communication.
(ii) Monitoring and forecasting of weather.

Q4. Name a satellite, which has revolutionised communication system in India. State its two important functions.

Ans4. INSAT-1B.
Functions: (i) Weather forecasting.
(ii) Satellite communication, e.g., TV transmission.


Three mark questions with answers

Q1. Mention any three areas of application of space science and one characteristic feature of the use of satellite in each case.

Ans1. (i) Satellite communication by using communication (geostationary) satellite.
(ii) Study of natural resources from outer space by using remote sensing satellites.
(iii) Weather monitoring. This is done by using geostationary satellites.

Q2. Write the working of a communication satellite.

Ans2. Waves employed for T.V transmissions have high frequency i.e., 109 to 1010 Hz. These waves are beamed up by a T.V transmitter. These are amplified and reflected back by the communication satellite to the ground station. This process is called satellite communication. It is very useful for long distance communication such as, T.V transmission, long distance telephone calls etc.

Q3. Name the three characteristics, which describe the orbit of an artificial satellite around the earth. Illustrate them on a diagram.

Ans3. Characteristics of an orbit
(i) Apogee (ii) Perigee (iii) Inclination

Q4. What is remote sensing? Why is the orbit of a remote sensing satellite called Sun Synchronous Orbit? Give any two uses of a remote sensing satellite.

Ans4. Making observations from long distance with the help of modern electronic equipment is termed remote sensing.
A remote sensing satellite passes over a particular latitude at the same local time. In other words, the position of the sun with respect to a point on the earth remains almost the same as the satellite passes over it. That is why, the orbit of a remote sensing satellite is called sun synchronous orbit.
Uses:
(i) Study of forestry, ground water, and wasteland.
(ii) Estimation of crop yields and crop diseases.


Five mark questions with answers

Q1. With respect to space programmes in India discuss the basic requirements for attaining self-sufficiency in the field of space technology.

Ans1. In the year 1961, Government of India took initiative to start developing space programmes and entrusted this task to the Department of Atomic Energy. Two major objectives of India's space programme were identified:
(i) Rapid development of mass communication and education system in the remote areas.
(ii) Timely survey and management of natural resources of the country such as underground water, coal, petroleum etc.

It was also realised that overall development of the country can be supported very well by utilising the potential of space technology.
Indian Space Research Organisation (ISRO) was set up in 1972 with a view to achieving self-reliance in the field of space technology. The department of space implements its programmes through ISRO. For attaining self-sufficiency in the field of space technology it was necessary:

(i) To develop expertise in planning, designing and fabricating the space crafts for various purposes.
(ii) To develop technology for designing and fabricating launch vehicles.
(iii) For complete tracking, controlling and guiding the satellites. To monitor the satellites guiding the satellites.
(iv) To develop applications like long distance telephones, television broadcast, weather forecasting, tapping the hydrosphere etc.

Q2. What do you mean by space science and how India has progressed in the field of weather monitoring, remote sensing and information collection etc?

Ans. (Try yourself).