B. Fill in the Blanks (Book Work)
1.
When viewed from the top of the North Pole, Earth seems to be rotating from west
to east direction.
2.
During the rotation of the Earth, the part facing the Sun experiences daytime.
3.
In the month of December, the Northern hemisphere experiences winter
whereas the Southern hemisphere experiences summer.
4.
There is not much variation in the intensity of sunrise falling on the equator
in different months.
5.
We can safely watch lunar eclipse with our naked eye.
C. State True or False
1.
When the Moon is completely in the Earth's shadow, it is a total solar eclipse.
Answer: False.
Correct statement: When the Moon is completely in the Earth's shadow, it is a total
lunar eclipse.
2.
There are many superstitions associated with solar eclipse.
Answer: True.
3.
The Moon is smaller in size than the Sun.
Answer: True.
The Sun is much larger than the Moon in actual size.
4.
All stars and constellations appear to remain fixed in their position in the
sky.
Answer: False.
Correct statement: Stars and constellations appear to move across the sky
because of Earth's rotation, although their relative positions within a
constellation appear nearly unchanged.
5.
The Moon appears to rise in the west and set in the east.
Answer: False.
Correct statement: The Moon generally appears to rise in the east and set in
the west.
D. Odd One Out ( Notebook Work )
1.
Earth, Sun, Venus, Mercury
Odd one out: Sun
Reason: The Sun is a star, whereas Earth, Venus and Mercury are
planets.
2.
Big Dipper, Orion, Pole Star, Ursa Minor
Odd one out: Pole Star
Reason: Big Dipper, Orion and Ursa Minor are constellations,
whereas Pole Star is an individual star.
3.
Australia, Russia, Canada, United States of America
Odd one out: Australia
Reason: Australia lies mainly in the Southern Hemisphere, while
the others lie in the Northern Hemisphere.
4.
Australia, New Zealand, Turkey, Argentina
Odd one out: Turkey
Reason: Turkey lies in the Northern Hemisphere, while Australia,
New Zealand and Argentina are in the Southern Hemisphere.
E. Assertion–Reason
1. Assertion: While Aadhya is having lunch in New Delhi, Nitya in New York is sleeping because it is night there.
Reason: Earth rotates from west to east.
Answer: (a) Both Assertion and Reason are true, and Reason is the
correct explanation of the Assertion.
2. Assertion: Pole Star appears nearly stationary in the sky from Earth.
Reason: The stars do not appear to move in the sky.
Answer: (c) Assertion is true but Reason is false.
Explanation: The Pole Star appears nearly stationary because it lies
very close to the direction of Earth's rotational axis. Other stars appear to
move across the sky.
3. Assertion: Stars and constellations that appear in the east at sunset change during different months.
Reason: Earth takes 24 hours to complete one rotation.
Answer: (b) Both Assertion and Reason are true, but Reason is not the
correct explanation.
Explanation: The change in the constellations visible at a particular
time in different months is mainly due to Earth's revolution around the Sun,
not its daily rotation.
4. Assertion: Days are longer in summer than in winter in India.
Reason: India receives sunlight for more than 12 hours during summers as
it lies in the Northern Hemisphere.
Answer: (a) Both Assertion and Reason are true, and Reason correctly
explains the Assertion.
5. Assertion: It is advisable to watch a solar eclipse directly with your eyes.
Reason: The Sun is intense even during the eclipse.
Answer: (d) Assertion is false but Reason is true.
Correct statement: A solar eclipse should never be viewed directly with
naked eyes.
II. Logic-Based Questions
1.
The planet Venus cannot block the entire sunlight from reaching Earth. Why?
Venus cannot completely block the
Sun as seen from Earth because its apparent size in the sky is much smaller
than the Sun's apparent size. Therefore, Venus cannot cover the entire
visible disc of the Sun.
2.
Christmas is winter in India but summer in Australia. Why?
India is in the Northern
Hemisphere, while Australia is in the Southern Hemisphere. In
December, the Northern Hemisphere is tilted away from the Sun and experiences
winter, whereas the Southern Hemisphere is tilted towards the Sun and
experiences summer.
3.
Why is a total solar eclipse visible only for a few minutes?
A total solar eclipse occurs only
when the Moon's umbra falls on a particular region of Earth. Because
Earth and Moon are continuously moving, this shadow quickly moves across
Earth's surface. Therefore, totality lasts only for a short time.
4.
Sia noticed Saptarishi and Dhruva Tara on a clear May evening. Will she notice
them at the same position after a few hours?
Saptarishi: No. It will appear to have moved across the sky because of
Earth's rotation.
Dhruva Tara (Pole Star): It will appear almost at the same position because it lies
very close to the direction of Earth's rotational axis.
5.
Why can't solar eclipses be seen everywhere on Earth?
A solar eclipse can be seen only
from the region of Earth over which the Moon's shadow falls. Since the
Moon's shadow covers only a limited area of Earth's surface, a solar eclipse
cannot be seen everywhere.
III. Higher Order Thinking Skills
1.
How would seasonal patterns change if Earth's axis were tilted more than 23.5°?
If Earth's axis had a greater tilt:
- Summers would become hotter in the respective
hemispheres.
- Winters would become colder.
- The difference between summer and winter would become
greater.
- The variation in day and night length would also
increase.
- Polar regions would experience more extreme periods of
daylight and darkness.
2.
How do seasons differ between the Northern and Southern Hemispheres?
The seasons are opposite in
the two hemispheres.
|
Northern
Hemisphere |
Southern
Hemisphere |
|
Summer — June to August |
Winter — June to August |
|
Winter — December to February |
Summer — December to February |
|
Spring around March |
Autumn around March |
|
Autumn around September |
Spring around September |
3.
Differences between Solar and Lunar Eclipses
|
Solar
Eclipse |
Lunar
Eclipse |
|
Moon comes between Sun and Earth. |
Earth comes between Sun and Moon. |
|
Moon's shadow falls on Earth. |
Earth's shadow falls on Moon. |
|
Occurs during a New Moon. |
Occurs during a Full Moon. |
|
Visible from a limited region of
Earth. |
Can be seen from a much larger
part of Earth's night side. |
|
Should not be viewed directly with
naked eyes. |
Can be viewed safely with naked
eyes. |
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