NCERT Class 8 Science MCQ | Chapter 11: Keeping Time with the Skies
1. Why does the Moon appear to change its shape during a month?
(A) The Moon changes its actual shape every night
(B) We see different portions of its illuminated part from Earth
(C) Earth’s shadow always covers the Moon
(D) The Moon produces different amounts of light
Answer: (B) We see different portions of its illuminated part from Earth
2. Why does the Moon shine?
(A) It produces its own light
(B) It reflects sunlight
(C) It reflects light from Earth
(D) It receives light from stars
Answer: (B) It reflects sunlight
3. What are the changing shapes of the bright portion of the Moon seen from Earth called?
(A) Seasons
(B) Phases of the Moon
(C) Eclipses
(D) Orbits
Answer: (B) Phases of the Moon
4. Which day is the Moon seen as a full bright circle?
(A) New Moon day
(B) Full Moon day
(C) Crescent day
(D) Eclipse day
Answer: (B) Full Moon day
5. What is the day when the Moon is not visible from Earth called?
(A) Full Moon day
(B) New Moon day
(C) Gibbous day
(D) Waning day
Answer: (B) New Moon day
6. What is the period during which the bright portion of the Moon increases called?
(A) Waning period
(B) Waxing period
(C) Eclipse period
(D) Solar period
Answer: (B) Waxing period
7. What is the period during which the bright portion of the Moon decreases called?
(A) Waxing period
(B) Waning period
(C) Lunar year
(D) Solar period
Answer: (B) Waning period
8. In India, the waxing period of the Moon is generally called:
(A) Krishna Paksha
(B) Shukla Paksha
(C) Amavasya
(D) Purnima
Answer: (B) Shukla Paksha
9. In India, the waning period of the Moon is generally called:
(A) Shukla Paksha
(B) Krishna Paksha
(C) Purnima
(D) Uttarayan
Answer: (B) Krishna Paksha
10. Approximately how long does it take for the Moon to complete one cycle from one full Moon to the next?
(A) 7 days
(B) 15 days
(C) 29.5 days
(D) 365 days
Answer: (C) 29.5 days
11. Why are the phases of the Moon not caused by Earth’s shadow?
(A) The Moon does not revolve around Earth
(B) The phases result from the changing relative positions of the Sun, Moon, and Earth
(C) Earth has no shadow
(D) The Moon produces its own light
Answer: (B) The phases result from the changing relative positions of the Sun, Moon, and Earth
12. On a full Moon day, the Moon is nearly:
(A) In the same direction as the Sun
(B) Opposite the Sun in the sky
(C) Directly between Earth and the Sun
(D) Below the horizon throughout the day
Answer: (B) Opposite the Sun in the sky
13. Which Moon is easiest to spot at sunset according to the chapter?
(A) Waxing Moon
(B) Waning Moon
(C) New Moon
(D) Full Moon only
Answer: (A) Waxing Moon
14. Which Moon is easiest to spot at sunrise?
(A) Waxing Moon
(B) Waning Moon
(C) New Moon
(D) Full Moon only
Answer: (B) Waning Moon
15. About how much later does the Moon rise each day compared with the previous day?
(A) 10 minutes
(B) 25 minutes
(C) 50 minutes
(D) 2 hours
Answer: (C) 50 minutes
16. What mainly causes the apparent daily movement of the Sun across the sky?
(A) Revolution of the Moon around Earth
(B) Rotation of Earth around its axis
(C) Revolution of Earth around the Sun
(D) Rotation of the Moon
Answer: (B) Rotation of Earth around its axis
17. What is the mean solar day approximately equal to?
(A) 12 hours
(B) 20 hours
(C) 24 hours
(D) 30 hours
Answer: (C) 24 hours
18. Which natural cycle forms the basis of a month?
(A) Earth’s rotation around its axis
(B) Moon’s cycle of phases
(C) Earth’s revolution around the Sun
(D) Daily movement of stars
Answer: (B) Moon’s cycle of phases
19. Which natural cycle is used to define a year?
(A) Earth’s revolution around the Sun and the cycle of seasons
(B) Moon’s rotation around Earth
(C) Earth’s daily rotation
(D) Moon’s phases only
Answer: (A) Earth’s revolution around the Sun and the cycle of seasons
20. How long does Earth take approximately to complete one revolution around the Sun?
(A) 24 hours
(B) 29.5 days
(C) 365 and a quarter days
(D) 100 days
Answer: (C) 365 and a quarter days
21. What is a lunar calendar primarily based on?
(A) The cycle of seasons
(B) The phases of the Moon
(C) Earth’s rotation only
(D) The movement of artificial satellites
Answer: (B) The phases of the Moon
22. Why do luni-solar calendars sometimes add an extra month?
(A) To make every month exactly 30 days
(B) To keep the lunar calendar in step with the solar year and seasons
(C) To increase the number of days in a week
(D) To match the Moon’s rotation with Earth’s rotation
Answer: (B) To keep the lunar calendar in step with the solar year and seasons
23. Why does the Gregorian calendar have a leap year?
(A) The Moon takes 29.5 days to complete its phases
(B) Earth takes nearly an extra quarter of a day beyond 365 days to complete its revolution
(C) The Sun takes 24 hours to rise
(D) The lunar year has 354 days
Answer: (B) Earth takes nearly an extra quarter of a day beyond 365 days to complete its revolution
24. Which of the following is a use of artificial satellites?
(A) Communication and navigation
(B) Weather monitoring
(C) Scientific research
(D) All of the above
Answer: (D) All of the above
25. Which statement correctly describes artificial satellites?
(A) They are natural objects that orbit only the Moon
(B) They are human-made objects launched from Earth that orbit Earth
(C) They produce the light of the Moon
(D) They are responsible for causing Moon phases
Answer: (B) They are human-made objects launched from Earth that orbit Earth
NCERT Class 8 Science MCQ | Chapter 11: Keeping Time with the Skies
Assertion–Reason Questions
Directions: Choose the correct option:
(A) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
(B) Both Assertion and Reason are true, but Reason is not the correct explanation of Assertion.
(C) Assertion is true, but Reason is false.
(D) Assertion is false, but Reason is true.
1. Assertion: The Moon appears to change its shape during a month.
Reason: We see different portions of the Moon’s illuminated half as the Moon revolves around the Earth.
Answer: (A)
2. Assertion: The phases of the Moon are not caused by the shadow of the Earth.
Reason: The phases occur due to the changing relative positions of the Sun, Moon, and Earth as the Moon revolves around the Earth.
Answer: (A)
3. Assertion: A full cycle of the Moon’s phases takes about a month.
Reason: The Moon takes about 29.5 days to complete one cycle of its phases.
Answer: (A)
4. Assertion: A solar calendar is related to the cycle of seasons.
Reason: The seasons are caused by the revolution of the Earth around the Sun.
Answer: (A)
5. Assertion: Artificial satellites are useful for communication, navigation, weather monitoring, and scientific research.
Reason: Artificial satellites are human-made objects launched into space that orbit the Earth.
Answer: (B)
