CHAPTER 12
EARTH, MOON AND THE SUN
EXERCISE
Q. 1. Fill up the blanks
(i) The Earth rotates from ______ direction to ______ direction.
Ans. west, east
(ii) The movement of an object around another object is called the ______.
Ans. revolution
(iii) The imaginary line on which the Earth rotates is called ______.
Ans. axis of rotation
Q. 2. State whether the following statements are true or false?
(i) Rotation refers to an object spinning around its own axis. (True/False)
Ans. True
(ii) The Earth’s axis of rotation is upright with respect to the orbit. (True/False)
Ans. False
(iii) Solar eclipse happens in every year. (True/False)
Ans. False
(iv) A “diamond ring” is seen after a lunar eclipse. (True/False)
Ans. False
Q. 3.
Jonaki notices a group of stars at the midnight in the winter solstice. Will she notice the same group of stars at midnight in the winter solstice next year on the same day?
Ans. Yes, she will notice.
Q. 4.
Why do you think plants move eastward even though the Earth rotates from West to East?
Ans. The planets also move eastward like the Earth, because they were formed from a massive, rotating disk of gas and dust that spun in that direction when the solar system was created.
Q. 5.
What differences would happen if the Earth was not tilted on its axis?
Ans. If the earth was not tilted on its axis, seasons would not have been caused on the earth.
Q. 6.
A friend says, “Solar eclipses occur during New Moon. Then why don’t eclipses occur every New Moon?” How would you respond to him using your understanding from the chapter?
Ans. Solar eclipses take place only on New Moon days, but they do not happen on every New Moon. This is because the Moon’s orbit around the Earth is slightly tilted, about 5°, compared to the Earth’s orbit around the Sun. As a result, during most New Moons, the Sun, Moon and Earth do not come exactly in a straight line. Therefore, a solar eclipse does not occur every time.
Q. 7. Darken the circle of correct answer:
(i) In which phase of the Moon, does a solar eclipse occur?
(a) New Moon
(b) Full Moon
(c) First quarter
(d) Last quarter
Ans. (a)
(ii) What is the order of the Sun, Earth and Moon during a solar eclipse?
(a) Earth → Sun → Moon
(b) Sun → Moon → Earth
(c) Earth → Moon → Sun
(d) Moon → Sun → Earth
Ans. (b)
(iii) One morning, Madhurjya was talking with his cousin who was in United States of America (USA), his cousin was about to sleep as it was night-time there. What is the main reason behind this time difference?
(a) The USA is farther from the Sun
(b) The Moon blocks sunlight from reaching the USA
(c) The Earth’s revolution causes day and night.
(d) The Earth’s rotation causes different areas to face the Sun at different times.
Ans. (d)
(iv) Teacher asked, “Why do the places near the Poles experience long days in summer and long nights in winter”? Four students answered. Who do you think answered correctly?
(a) The Sun moves closer to the Poles in summer.
(b) The Sun moves farther from the Poles during winter.
(c) The Earth spins on its axis near the Poles.
(d) The tilt of Earth’s axis affects sunlight during revolution.
Ans. (d)
Q. 8.
Label the followings in the given figure of the Earth.
- North Pole and South Pole
- Earth’s axis of rotation
- Northern Hemisphere
- Southern Hemisphere
- Earth
- Equator
Q. 9. Draw and label the diagram:
(a) Lunar eclipse
(b) Solar eclipse
Ans. (a) Lunar eclipse
**(b) Solar eclipse
Q. 10.
How do you keep yourself safe if you want to see the solar eclipse?
Ans. To see the solar eclipse safely, we should use proper eye protection like specialised solar filters or eclipse glasses. We should not view solar eclipse directly or through sunglasses, binoculars or telescopes.
Q. 11.
If you are 11 years old, what will be your age after the Earth completes one revolution around the Sun. Explain.
Ans. My age will be 12 years after the Earth completes one revolution around the Sun. This is because, the Earth takes approximately 365 days to complete one revolution around the sun. This period is referred to as one year.
Q. 12. Find the odd one out and justify your answer
(a) Moon, Mercury, Venus
(b) Day, Year, Month, Eclipse
Ans.
(a) Moon. Because the Moon is a natural satellite of the Earth, whereas Mercury and Venus are two planets of the Sun.
(b) Eclipse. Because eclipse is a celestial phenomenon, whereas Day, Year and Month are some units of time.
Q. 13. Match the following
Column A
(i) Seasons
(ii) Solar eclipse
(iii) Day and night
(iv) Lunar eclipse
Column B
(a) Moon blocks sunlight
(b) Caused by Earth’s tilt and revolution
(c) Earth blocks the moon
(d) Caused by earth’s rotation
Ans. (i) – (b), (ii) – (a), (iii) – (d), (iv) – (c)
OLD Question Answer
The light
1) Fill in the blanks-
(a) An image that cannot be found on the screen is called a spurious image .
(b) The images formed by a convex mirror are always equal in size to the object.
c) The image formed by a plane mirror is always equal in size to the object.
d) The image on the screen is called true .
e) The image formed by a concave lens cannot be found on the screen.
2. Write ‘True’ if the following statements are true and ‘False’ if they are false.
a) We can form a magnified and standing image by means of a convex mirror.
Answer: True.
b) Concave lenses form spurious images. (True\False)
Answer: True.
c) We can form true, magnified and inverted images with concave mirrors. (True\False)
Answer: True.
d) Honest, the image cannot be found on the screen. (True\False)
Answer: False.
E. A concave mirror always forms a true image. (True\False)
Answer: False.
3. Match the statements in column 1 with one or more statements in column
| Column1 | Column2 | |
| a) It is done as a flat mirror. | 1) Used as a magnifying glass. | |
| b) A convex mirror | 2) Target images can be formed scattered over a large area | |
| C) A convex lens | 3. Used by dentists to see magnified images of teeth. | |
| D. A concave mirror | 4. The image is always inverted and magnified. | |
| E. A concave lens | 5) The image is vertical and equal in size to the target object. | |
| 6. The image is erect and constricted relative to the target | ||
4. Describe the image characteristics formed by a plane mirror.
Answer:-
5. Find those letters in the English alphabet or any other language alphabet you know that have no shape difference from the image formed by a plane mirror. Discuss your results.
Answer:-
6) What is meant by false reflection? Describe a situation in which a spurious image is formed .
Answer: An image formed in a plane mirror that cannot be cast on the screen is called a false image.
7. Write down two differences between convex and concave lenses.
Answer: Convex lenses can form true and inverted images.
Concave lenses, on the other hand, always form a vertical, distorted, and concave image relative to the object.
8. Write down one use for each of concave and convex mirrors.
Answer: Use of concave mirrors Concave mirrors are used by doctors to examine the eyes, ears, nose and throat.
9. What kind of mirror forms a true reflection?
Answer:-
10. What kind of lens always forms a false image?
Answer:-
Choose the correct answer to questions 11 to 13:
11. 11. Objects that are larger than the target and can form a false image are—
( a ) Concave lens b ) Concave mirror
( c ) Convex mirror ( d ) Plane mirror
12. David is observing his reflection in a flat mirror. The distance between the mirror and his reflection is 4 m. If he moves 1 m to the mirror goes forward , then the distance between David and his reflection will be
( a ) 3 m ( b ) 5 m
( c ) 6 m ( d ) 8 m
13. 13. The rearview mirror of a car is a flat mirror. A driver is reversing his car at a speed of 2 m/s. The driver saw in his rearview mirror the reflection of a truck parked behind him. The reflection of the truck will speed up the approach of the driver
(a) 1 m. / s . (b) 2 min. / s .
(c) 4 m. / s . (d) 8 m. / s .
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