Q1: Earth rotates on its axis once every __________. (a) 12 hours (b) 24 hours (c) 365 days (d) 30 days
Solution:
Ans: (b) Explanation: Earth completes one full rotation on its axis in approximately 24 hours, which is one day. This rotation causes the cycle of day and night. Option (a) is incorrect because 12 hours is half a rotation. Option (c) represents Earth's revolution around the Sun, not rotation. Option (d) is roughly one month, which is unrelated to Earth's rotation.
Q2: What is the primary reason Earth experiences seasons? (a) The distance between Earth and the Sun changes throughout the year (b) The tilt of Earth's axis as it revolves around the Sun (c) The Moon blocks sunlight during certain times of the year (d) Earth rotates faster during summer months
Solution:
Ans: (b) Explanation: Earth's seasons are caused by the tilt of Earth's axis at approximately 23.5 degrees. As Earth revolves around the Sun, different parts of Earth receive more direct sunlight at different times of the year. Option (a) is a common misconception; the distance change has minimal effect on seasons. Option (c) describes an eclipse, not seasons. Option (d) is incorrect because Earth's rotation rate remains constant.
Q3: How long does it take Earth to complete one revolution around the Sun? (a) 1 day (b) 1 month (c) 1 year (d) 1 week
Solution:
Ans: (c) Explanation: Earth completes one full revolution around the Sun in approximately 365.25 days, which equals one year. This is why we have leap years every four years to account for the extra 0.25 days. Option (a) represents one rotation. Option (b) is roughly the time for the Moon to orbit Earth. Option (d) is too short for any significant astronomical cycle.
Q4: During which season in the Northern Hemisphere is the North Pole tilted toward the Sun? (a) Winter (b) Spring (c) Summer (d) Fall
Solution:
Ans: (c) Explanation: During summer in the Northern Hemisphere, the North Pole is tilted toward the Sun, resulting in longer days and more direct sunlight. This occurs around June 21, the summer solstice. During winter (option a), the North Pole tilts away from the Sun. Spring and fall (options b and d) are transitional seasons when neither pole is significantly tilted toward or away from the Sun.
Q5: What causes day and night on Earth? (a) Earth's revolution around the Sun (b) Earth's rotation on its axis (c) The Moon's shadow on Earth (d) Clouds blocking sunlight
Solution:
Ans: (b) Explanation: Day and night are caused by Earth's rotation on its axis. As Earth rotates, different parts face the Sun (experiencing day) while other parts face away (experiencing night). Option (a) describes revolution, which causes seasons. Option (c) describes a lunar eclipse. Option (d) affects weather but not the day-night cycle.
Q6: An equinox occurs when __________. (a) The North Pole is tilted most toward the Sun (b) The South Pole is tilted most toward the Sun (c) Neither pole is tilted toward or away from the Sun (d) Earth is closest to the Sun
Solution:
Ans: (c) Explanation: During an equinox, Earth's axis is tilted neither toward nor away from the Sun, and the Sun appears directly over the equator. This results in approximately equal hours of daylight and darkness worldwide. There are two equinoxes per year: the vernal (spring) equinox around March 20 and the autumnal (fall) equinox around September 22. Options (a) and (b) describe solstices. Option (d) is incorrect as distance from the Sun does not define an equinox.
Q7: Which motion of Earth is responsible for the yearly cycle of seasons? (a) Rotation (b) Revolution (c) Precession (d) Oscillation
Solution:
Ans: (b) Explanation: Earth's revolution around the Sun, combined with its axial tilt, creates the yearly cycle of seasons. As Earth orbits the Sun over 365.25 days, different hemispheres receive varying amounts of direct sunlight. Option (a) rotation causes day and night, not seasons. Option (c) precession is a slow wobble taking thousands of years. Option (d) is not a recognized motion of Earth in this context.
Q8: What is the approximate angle of Earth's axial tilt? (a) 0 degrees (b) 15 degrees (c) 23.5 degrees (d) 45 degrees
Solution:
Ans: (c) Explanation: Earth's axis is tilted at approximately 23.5 degrees from the perpendicular to its orbital plane. This tilt is crucial for causing seasons. If Earth had no tilt (option a), there would be no seasons. Options (b) and (d) are incorrect values that would result in very different seasonal patterns than what we experience.
Section B: Fill in the Blanks
Q9: The imaginary line that runs through Earth from the North Pole to the South Pole is called Earth's __________.
Solution:
Ans: axis Explanation: Earth's axis is the imaginary line around which Earth rotates. It passes through both the North and South Poles and is tilted at 23.5 degrees relative to Earth's orbital plane.
Q10: The path that Earth follows as it travels around the Sun is called its __________.
Solution:
Ans: orbit Explanation: Earth's orbit is the elliptical path it follows around the Sun during its revolution. One complete orbit takes approximately 365.25 days, or one year.
Q11: The longest day of the year in the Northern Hemisphere occurs during the __________, around June 21.
Solution:
Ans: summer solstice Explanation: The summer solstice occurs when the North Pole is tilted most directly toward the Sun, resulting in the longest period of daylight in the Northern Hemisphere. This happens around June 21 each year.
Q12: When it is summer in the Northern Hemisphere, it is __________ in the Southern Hemisphere.
Solution:
Ans: winter Explanation: Due to Earth's axial tilt, when the Northern Hemisphere is tilted toward the Sun (experiencing summer), the Southern Hemisphere is tilted away from the Sun (experiencing winter). The seasons are opposite in the two hemispheres.
Q13: A __________ occurs twice a year when day and night are approximately equal in length all over Earth.
Solution:
Ans: equinox Explanation: An equinox occurs when the Sun is positioned directly above Earth's equator, and neither hemisphere is tilted toward or away from the Sun. This results in nearly equal hours of daylight and darkness globally. The two equinoxes are the vernal (spring) and autumnal (fall) equinoxes.
Q14: Earth's spinning on its axis is called __________.
Solution:
Ans: rotation Explanation:Rotation is the spinning motion of Earth on its axis. This rotation takes approximately 24 hours to complete and is responsible for the cycle of day and night.
Section C: Word Problems
Q15: Sarah lives in Chicago, which is in the Northern Hemisphere. On June 21, she notices that the Sun is visible for 15 hours. Six months later, on December 21, the Sun is only visible for 9 hours. Explain why the length of daylight changes so much between these two dates.
Solution:
Ans: Final Answer: The length of daylight changes because of Earth's axial tilt of 23.5 degrees. On June 21 (summer solstice), the North Pole is tilted toward the Sun, so the Northern Hemisphere receives more direct sunlight and longer days. On December 21 (winter solstice), the North Pole is tilted away from the Sun, resulting in less direct sunlight and shorter days in the Northern Hemisphere.
Q16: A student observes that the Sun rises in the east and sets in the west every day. If Earth rotates counterclockwise when viewed from above the North Pole, explain how this rotation causes the Sun to appear to move from east to west across the sky.
Solution:
Ans: Final Answer: As Earth rotates counterclockwise (from west to east) on its axis, different parts of Earth's surface move into and out of sunlight. From our perspective on Earth's surface, we are moving eastward, which makes the Sun appear to move in the opposite direction-from east to west across the sky. This is an example of apparent motion caused by Earth's rotation.
Q17: During summer vacation, Marcus travels from New York City (Northern Hemisphere) to Buenos Aires, Argentina (Southern Hemisphere). He leaves New York in July when it is very hot. When he arrives in Buenos Aires, he is surprised to find cold weather. Explain why the seasons are different in these two locations at the same time.
Solution:
Ans: Final Answer: The seasons are opposite in the Northern and Southern Hemispheres because of Earth's axial tilt. In July, the Northern Hemisphere is tilted toward the Sun, experiencing summer with hot weather. At the same time, the Southern Hemisphere is tilted away from the Sun, experiencing winter with cold weather. This is why Marcus experienced summer in New York but winter in Buenos Aires during the same month.
Q18: If Earth's axis were not tilted and instead was perpendicular to its orbital plane around the Sun, how would this affect the seasons on Earth? Explain your reasoning.
Solution:
Ans: Final Answer: If Earth's axis were not tilted, there would be no seasons. Every location on Earth would receive approximately the same amount of sunlight throughout the year. The Sun would always rise and set at the same positions, and day and night would be equal in length (12 hours each) every day of the year at all locations. The variation in seasons exists because of the 23.5-degree tilt of Earth's axis.
Q19: A class is studying Earth's rotation. They learn that Earth rotates 360 degrees in 24 hours. Calculate how many degrees Earth rotates in one hour. Show your work.
Solution:
Ans: Final Answer: Earth rotates 15 degrees per hour.
Calculation: Total rotation in 24 hours = 360 degrees Rotation per hour = 360 ÷ 24 = 15 degrees per hour
Q20: On March 20, the vernal equinox, a student in Ecuador (located on the equator) measures the length of daytime and nighttime. She finds that both are approximately 12 hours long. Three months later, on June 21 (summer solstice), she measures again and finds that daytime and nighttime are still about 12 hours each. Explain why the length of day and night stays approximately the same at the equator throughout the year.
Solution:
Ans: Final Answer: At the equator, the length of day and night remains approximately 12 hours throughout the year because the equator is positioned halfway between the North and South Poles. Regardless of Earth's tilt during different seasons, the equator receives relatively consistent amounts of sunlight year-round. While the hemispheres experience varying daylight hours due to the axial tilt, the equator maintains nearly equal day and night lengths because it is always perpendicular to the Sun's rays at solar noon.
shortcuts and tricks, Worksheet (with Solutions): Earth in Space, Free, Previous Year Questions with Solutions, Important questions, past year papers, Exam, Worksheet (with Solutions): Earth in Space, pdf , ppt, Extra Questions, Summary, Worksheet (with Solutions): Earth in Space, Viva Questions, Semester Notes, MCQs, video lectures, practice quizzes, study material, mock tests for examination, Objective type Questions, Sample Paper;
