CBSE: Check NCERT based important extra questions & answers of CBSE Class 9 Science (Chapter 10 Gravitation). These CBSE Class 9 extra questions & answers are important for the preparation of the upcoming CBSE Class 9 Science Exam 2020-21. Any of these questions might be asked in the exam with slight modification.
CBSE Class 9 Science Exam 2020-21: NCERT Based Important Extra Questions (With Answers) Chapter 10 - Gravitation
Question: Fill in the blanks
All objects experience a force of _________buoyancy when they are immersed in a fluid.
Answer:
All objects experience a force of buoyancy when they are immersed in a fluid.
Question: The mass of an object is 80 kg on earth. What is its mass on Jupiter?
Answer:
The mass of the object on Jupiter will also be 80 kg.
CBSE Class 9 Revised Syllabus for 2020-2021
Question: Define weight of a body?
Answer:
The weight of a body is the force with which the earth attracts it.
Question: The value of acceleration due to gravity
(a) is same on equator and poles
(b) is least on poles
(c) is least on equator
(d) increases from pole to equator
Answer:
(c)
The value of acceleration due to gravity is least on the equator.
Question: In the relation F = G M m/d2, the quantity G
(a) depends on the value of g at the place of observation
(b) is used only when the earth is one of the two masses
(c) is greatest at the surface of the earth
(d) is universal constant of nature
Answer:
G is the universal constant of nature.
Question: The atmosphere is held to the earth by
(a) gravity
(b) wind
(c) clouds
(d) earth’s magnetic field
Answer:
(a) gravity
Question: Suppose gravity of earth suddenly becomes zero, then in which direction will the moon begin to move if no other celestial body affects it?
Answer:
The moon will begin to move in a straight line in the direction in which it was moving at that instant because the circular motion of the moon is due to centripetal force provided by the gravitational force of earth.
Question: The earth is acted upon by gravitation of Sun, even though it does not fall into the Sun. Why?
Answer:
The gravitational force is responsible for providing the necessary centripetal force.
Question: The weight of an object at the centre of the earth of radius R is
(a) zero
(b) infinite
(c) R times the weight at the surface of the earth
(d) 1/R2 times the weight at surface of the earth
Answer:
(a) Zero.
Question: An object weighs 10 N in air. When immersed fully in water, it weighs only 8 N. The weight of the liquid displaced by the object will be
(a) 2 N
(b) 8 N
(c) 10 N
(d) 12 N
Answer:
(a) 2 N.
CBSE Class 9 New Study Material for 2020-2021: Download Best Resources for Self-Study
