Class 9 Rotation and Revolution Mock Test (ICSE)

Topics in Rotation and Revolution

• Rotation and its effects
• Day and night
• Coriolis effect
• Revolution and seasons
• Equinoxes and solstices

Rotation and Revolution practice questions with answers

1. Q1Multiple choice·1 mark
   The apparent daily east-to-west movement of the Sun across the sky is caused by:

   1. (a)The revolution of the Earth around the Sun in an elliptical orbit.
   2. (b)The rotation of the Earth from west to east on its axis.
   3. (c)The inclination of the Earth's axis.
   4. (d)The gravitational pull of the Moon on the Earth.
   Show answer and step marks

   1. Correct option: (b)+1

   Answer: (b)
2. Q2Multiple choice·1 mark
   What is the primary cause of changes in seasons on the Earth?

   1. (a)The Earth's rotation on its axis combined with its spherical shape
   2. (b)The tilt of the Earth's axis combined with its revolution around the Sun
   3. (c)The changing Earth-Sun distance combined with the Earth's revolution
   4. (d)The tilt of the Earth's axis combined with its daily rotation from west to east
   Show answer and step marks

   1. Correct option: (b) The tilt of the Earth's axis combined with its revolution around the Sun. As the tilted Earth revolves, each hemisphere leans towards the Sun for part of the year, changing the angle of the Sun's rays and the length of day.+1

   Answer: (b)
3. Q3Multiple choice·1 mark
   At which of the following locations on the Earth's surface is the Coriolis effect zero?

   1. (a)Equator
   2. (b)Tropic of Cancer
   3. (c)Poles
   4. (d)Arctic Circle
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   1. Correct option: (a) Equator+1

   Answer: (a)
4. Q4Short answer·2 marks
   Explain why places located in the east experience sunrise earlier than places located in the west.
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   1. The Earth rotates on its axis from west to east.+1
   2. Consequently, eastern longitudes come into view of the Sun earlier during rotation than western longitudes.+1

   Answer: Earth rotates from west to east; eastern longitudes face the Sun first.
5. Q5Long answer·4 marks
   (a) What is meant by the Coriolis effect? State its primary cause. [2] (b) How does the Coriolis effect impact the direction of winds in the Northern and Southern Hemispheres according to Ferrel's Law? [2]
   Show answer and step marks

   1. (a) Definition: The Coriolis effect is an apparent force caused by the Earth's rotation that deflects moving objects, such as winds and ocean currents, from their original straight path.+1
   2. (a) Cause: It is caused by the rotation of the Earth on its axis from west to east.+1
   3. (b) According to Ferrel's Law, winds are deflected to the right of their path in the Northern Hemisphere.+1
   4. (b) Winds are deflected to the left of their path in the Southern Hemisphere.+1

   Answer: (a) An apparent force that deflects moving winds and currents from a straight path; it is caused by the Earth's rotation from west to east. (b) Winds are deflected to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.
6. Q6Long answer·4 marks
   (a) What is meant by the Coriolis effect? State its main cause. [2] (b) Explain how the Coriolis effect influences the direction of planetary winds in the Northern and Southern Hemispheres. [2]
   Show answer and step marks

   1. (a) Definition: An apparent force generated by the earth's rotation that deflects freely moving objects such as winds and ocean currents from their straight path.+1
   2. (a) Cause: The rotation of the earth on its axis from west to east, which causes different latitudes to move at different linear speeds.+1
   3. (b) Northern Hemisphere: Due to the Coriolis effect, winds and moving air masses are deflected to the right of their path of motion.+1
   4. (b) Southern Hemisphere: Winds and moving air masses are deflected to the left of their path of motion.+1

   Answer: (a) An apparent force due to the Earth's rotation that deflects freely moving winds and currents from their straight path; it is caused by the rotation of the Earth from west to east. (b) Winds are deflected to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.

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