Balbharti Maharashtra State Board Class 9 Science Solutions Chapter 18 Observing Space: Telescopes Notes, Textbook Exercise Important Questions and Answers.
Class 9 Science Chapter 18 Observing Space: Telescopes Textbook Questions and Answers
1. Fill in the blanks with the proper words.
a. The wavelength of visible light is between …………………..….. and …………………..…. .
b. GMRT is used for …………………..….. waves.
c. A certain X-ray telescope is named after scientist …………………..…. .
d. The first scientist to use a telescope for space observations …………………..…. .
e. The biggest optical telescope in India is situated at …………………..…. .
2. Form pairs
| Column ‘A’ | Column ‘B’ |
| (1) X-rays | (a) GMRT |
| (2) Optical telescope | (b) ISRO |
| (3) Indian radio telescope | (c) Hubble |
| (4) Launching artificial-satellite | (d) Chandra |
Answer:
(1 – d),
(2 – c),
(3 – a),
(4 – b),
3. What are the difficulties in using ground-based optical telescopes? How are they overcome?
Answer:
Difficulties:
Solution:
4. Which type of telescopes can be made using a concave mirror, convex mirror, plane mirror, and a lens? Draw diagrams of these telescopes.
Answer:
5. Study the figure and answer the following questions:
a. What type of telescope is shown in the figure?
b. Label the main parts of the telescope.
c. Which type of mirror does the telescope use?
d. What other type of telescope uses a curved mirror?
e. Explain the working of the above telescope.
Answer:
(a) The Newtonian telescope (Reflecting telescope)
(b)
(c) Concave mirror
(d) The Cassegrain telescope
(e) Working.
6. Answer the following questions.
a. Explain the construction of Galileo’s telescope.
Answer:
b. Explain the construction of a radio telescope.
Answer:
c. Why are optical telescopes located in uninhabited places on mountains?
Answer:
d. Why can an X-ray telescope not be based on the earth?
Answer:
Class 9 Science Chapter 18 Observing Space: Telescopes Intext Questions and Answers
Question 1.
What is meant by space observation? Why is it important?
Answer:
The observation of distant planets, galaxies and other astronomical objects is called as space observation.
Question 2.
What is the difference between sky and space?
Answer:
Sky: It is a layer of gas that surrounds the earth in which sunlight is scattered making it visible from the surface of the earth.
Space: The vast emptiness beyond the sky is called as space.
Class 9 Science Chapter 18 Observing Space: Telescopes Additional Important Questions and Answers
Choose and write the correct options:
Question 1.
The first telescope was invented by
(a) Einstein
(b) Galileo
(c) Newton
(d) Mendel
Answer:
(b) Galileo
Question 2.
Eight is an wave.
(a) electric
(b) magnetic
(c) electromagnetic
(d) mechanical
Answer:
(c) electromagnetic
Question 3.
Visible radiation telescopes are also called as
(a) Gamma Ray telescopes
(b) Optical telescopes
(c) X-ray telescopes
(d) Radio telescopes
Answer:
(b) Optical telescope
Question 4.
Reflecting telescopes are mainly of two types : ……………….. and ………………. .
(a) Newtonian and Galileoan
(b) Optical and Cassegrain
(c) Newtonian and Cassegrain
(d) Optical and Refracting
Answer:
(c) Newtonian and cassegrain
Question 5.
Giant Meterwave Radio Telescope (GMRT) has been erected at near Pune.
(a) Asangaon
(b) Talegaon
(c) Narayangaon
(d) Bhategaon
Answer:
(c) Narayangaon
Question 6.
Visible light coming from heavenly bodies have to pass through the to reach the earth surface.
(a) stratosphere
(b) troposphere
(c) atmosphere
(d) biosphere
Answer:
(c) atmosphere
Question 7.
To collect the maximum amount of light coming from an object, the objective lens should be made as as possible.
(a) large
(b) small
(c) circular
(d) flat
Answer:
(a) large
Question 8.
The images formed by lenses have errors of colours. This is called
(a) chromatic disruption
(b) chromatic aberration
(c) chromatic reflection
(d) chromatic reaction
Answer:
(b) chromatic aberration
Question 9.
Radio telescope is made up of one or more dishes of shape.
(a) spherical
(b) hyperbolic
(c) parabolic
(d) hexagonal
Answer:
(c) parabolic
Match the columns:
Question 1.
| Column ‘A’ | Column ‘B’ |
| (1) X-rays | (a) GMRT |
| (2) Optical telescope | (b) ISRO |
| (3) Indian radio telescope | (c) Hubble |
| (4) Launching artificial satellite | (d) Chandra |
| (5) Radio waves | (e) telecommunication |
| (6) INSAT and GSAT | (f) longer than 20cm |
Answer:
(1 – d),
(2 – c),
(3 – a),
(4 – b),
(5 – f),
(6- e)
Question 2.
| Column ‘A’ | Column ‘B’ |
| (1) Micro waves (2) Infrared waves (3) Visible light rays (4) Ultraviolet rays (5) X-rays |
(a) 800 nm – 0.3mm (b) 360 pm – 400 nm (c) 3 pm – 300 pm (d) 400 nm – 800nm (e) 0.3 mm -20cm |
Answer:
(1 – e),
(2 – a),
(3 – d),
(4 – b),
(5 – c)
Define the following:
Question 1.
Visible radiation
Answer:
Light is an electromagnetic wave. Every wave has a characteristic wavelength. Our eyes can see only that light which has wavelengths between 400 nm to 800 nm. Such light is called visible radiation.
Question 2.
Reflecting Telescope
Answer:
When light falls on the mirror, it gets reflected. Telescopes that use concave mirrors are called reflecting telescope.
Question 3.
Optical telescopes
Answer:
Telescopes which are made from regular lenses and mirrors and used to see visible radiations coming from space are called optical telescopes.
Question 4.
Refracting Telescopes
Answer:
Light rays change their direction as they enter a lens from the atmosphere and again when they enter the atmosphere after passing through the lens. This is called refraction. The telescopes that use such lenses are called refracting telescopes.
Question 5.
Radio telescopes
Answer:
Many heavenly bodies emit radio waves in addition to visible radiation. A special type of telescope which is used to receive these rays are known as radio telescope.
Answer the following:
Question 1.
How do refracting telescopes work?
Answer:
Question 2.
What are the difficulties in using refracting telescopes?
Answer:
Question 3.
How does a radio telescope work?
Answer:
Question 4.
What are the two types of reflecting telescopes?
Answer:
Question 5.
What is the purpose of launching X-Ray telescope Chandra?
Answer:
Chandra was launched to study X-rays coming from heavenly objects. Special mirrors which . can reflect X-rays were used in this telescope.
Answer the following:
Question 1.
State some of the satellites and their uses.
Answer:
Question 2.
What is the specialty of the artificial satellite Astrosat?
Answer:
Answer in detail:
Question 1.
Explain any two space observation telescope.
Answer:
Hubble Telescope:
Chandra Telescope:
Question 2.
Write short note : GMRT
Answer: