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Science true or false.[1 Mark each]

PHYSICS CH9 Universe · Tamil Nadu Board STD 9 (Tamil - English Medium). 27 questions.

Questions

true or false.[1 Mark each]

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27 questions · timed · auto-graded

Question 11 Mark
State whether true or false. If false, correct the statement.

Mars is called the red planet.

  • True

  • False

Answer
Mars is called the red planet- True
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Question 21 Mark
State whether true or false. If false, correct the statement.

Satellites nearer to the Earth should have lesser orbital velocity.

  • True

  • False

Answer
False.

Correct statement: Nearer the object to the Earth, the faster is the required orbital velocity.

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Question 31 Mark
State whether true or false. If false, correct the statement.

Halley’s comet appears after nearly 67 hours.

  • True

  • False

Answer
False.

Correct statement: Halley’s comet appears after nearly every 76 years.

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Question 41 Mark
State whether true or false. If false, correct the statement.

ISS is a proof for international cooperation- 

  • True

  • False

Answer
ISS is a proof for international cooperation- True
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Question 51 Mark
Why are we able to see the Moon even though it is not a luminous body?
Answer
are able to see the moon, because it reflects the light of the Sun
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Question 61 Mark
What is a cosmic year?
Answer
The sun travelling at a speed of 250 km per second (9 lakhs km/h) takes about 225 million years to complete one revolution around the Milky Way. This period is called a cosmic year.
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Question 71 Mark
How is eye-tracking technology helpful?
Answer
Eye-tracking technology is helping disabled people with limited movement and speech.
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Question 81 Mark
What is a geostationary orbit?
Answer
A satellite stays in a fixed position relative to a point on Earth’s surface. That is, the satellite stays over the same spot all the time. This kind of orbit is called “Geostationary Orbit”.
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Question 91 Mark
Mention the factors responsible for motion of satellite.
Answer
  • Gravity and
  • The centripetal force are the factors responsible for motion of satellite
  •  
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Question 101 Mark
Give a reason for changes of seasons on Earth.
Answer
Semi major axis from sun, $R=149.6 \times 10^6 km$.
Period of Earth, $T=1$ year.
The ratio $=\frac{T^2}{R^3}=\frac{(1)^2}{\left(149.6 \times 10^6\right)^3}=2.98 \times 10^{-25}$ year $^2 / km ^3$.
  • Earth is not perpendicular to the plane of its orbit.
  • This tilt is responsible for the change of seasons on earth.
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Question 111 Mark
Define Period of rotation.
Answer
The time taken by a planet to complete one rotation is called its period of rotation.
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Question 121 Mark
What is an orbit?
Answer
A definite curved path in which a planet revolves around the sun is called an orbit.
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Question 131 Mark
Why is our galaxy called Milky way?
Answer
Our galaxy is called milky way galaxy, because it appears as a Milky band of light in the sky.
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Question 141 Mark
How are galaxies classified?
Answer
Depending on their appearance, galaxies are classified as
  • Spiral,
  • Elliptical, (or)
  • Irregular.
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Question 151 Mark
What is a galaxy?
Answer
A galaxy is a massive collection of gas, dust and billions of stars and their solar systems.
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Question 161 Mark
What is the universe?
Answer
The collection of all the things that exist in space is known as the universe.
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Question 171 Mark
The distance between Saturn and Uranus is about 10 times that between Earth and Mars.
Answer
False.
Correct statement: The distance between Saturn and Uranus is about 20 times that between Earth and Mars.
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Question 181 Mark
Comets revolve around the Sun in highly spiral orbits.
Answer
False.
Correct statement: Comets revolve around the Sun in highly elliptical orbits.
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Question 201 Mark
The axis of rotation of the Earth is perpendicular to the plane of its orbit.
Answer
False.
Correct statement: The axis of rotation of the Earth is not perpendicular to the plane of its orbit.
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Question 211 Mark
Mercury is a special planet from the Sun, almost the same size as Earth.
Answer
False.
Correct statement: Venus is a special planet from the Sun, almost the same size as Earth.
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Question 221 Mark
The rotation of the sun near the poles takes around 25.4 days.
Answer
False. Correct statement: The rotation of the Sun near the poles takes around 36 days.
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Question 231 Mark
The planets are revolving around the sun because of the gravitational force of attraction between them.
Answer
True.
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Question 241 Mark
Stars also appear to be in different colours depending on their composition of Gases.
Answer
False.
Correct statement: Stars also appear to be in different colours depending on their temperature.
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MCQ 261 Mark
The important thing about universe is that it is currently shrinking.
  • D
    The important thing about universe is that it is currently shrinking.
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true or false.[1 Mark each] - Science STD 9 Questions - Vidyadip