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Class 9 / Science (314 questions)
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by GIANSH GUPTA KHUNDKER
· Class 9
During oxidative phosphorylation in aerobic cellular respiration, which component of the mitochondrion builds up a high concentration gradient of protons (H⁺) to drive ATP synthesis via ATP synthase?
Science
Other
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by GIANSH GUPTA KHUNDKER
· Class 9
If 20.0 g of sulfur dioxide (SO₂) reacts with 10.0 g of oxygen (O₂) to produce sulfur trioxide (SO₃) according to the balanced equation 2SO₂(g) + O₂(g) → 2SO₃(g), what is the mass of the excess reactant remaining unreacted? (Molar masses: SO₂ = 64 g/mol, O₂ = 32 g/mol)
Science
Other
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by GIANSH GUPTA KHUNDKER
· Class 9
An object moves along a straight line such that its velocity v as a function of time t is given by v(t) = 3t² - 12t + 9 (in m/s). What is the total distance traveled by the object in the time interval from t = 0 s to t = 3 s?
Science
Other
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by GIANSH GUPTA KHUNDKER
· Class 9
Why do we fall ill?
Science
Why Do We Fall Ill
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by GIANSH GUPTA KHUNDKER
· Class 9
Which animal connective tissue houses mature chondrocytes inside structural cavities called lacunae?
Science
Other
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by GIANSH GUPTA KHUNDKER
· Class 9
Which component represents the only living cellular element found within complex Xylem tissue?
Science
Cell � The Fundamental Unit of Life
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by GIANSH GUPTA KHUNDKER
· Class 9
Which living plant tissue features structural pectin thickening at cell corners to provide flexible support?
Science
Other
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by GIANSH GUPTA KHUNDKER
· Class 9
Which process causes a red blood cell to shrink and crenate when placed in a hypertonic salt solution?
Science
Atoms and Molecules
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by GIANSH GUPTA KHUNDKER
· Class 9
What structure fails to form during plant cell cytokinesis if the Golgi apparatus is chemically inhibited?
Science
Cell � The Fundamental Unit of Life
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by GIANSH GUPTA KHUNDKER
· Class 9
A particle moves along a straight line so that its displacement s (in metres) at time t (in seconds) is s = t³ - 6t² + 9t + 4. What is the velocity of the particle when its acceleration becomes zero?
Science
Motion
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by GIANSH GUPTA KHUNDKER
· Class 9
An astronaut on a newly discovered planet drops a small 2 kg sphere from a height of 20 m. It takes exactly 4 seconds to hit the ground. The planet is perfectly spherical with a radius equal to half of the Earth's radius. Assuming no air resistance, what is the ratio of the mass of the planet to the mass of the Earth? (Take g on Earth = 10 m/s²)
Science
Other
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by GIANSH GUPTA KHUNDKER
· Class 9
Two bodies with masses M1 and M2 are separated by a distance R, and the gravitational force between them is F. If the mass of the first body is doubled, the mass of the second is halved, and the distance between their centres is reduced to R/2, what will be the new gravitational force?
Science
Atoms and Molecules
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by GIANSH GUPTA KHUNDKER
· Class 9
A sonar device on a submarine sends an ultrasound signal into the ocean. The signal reflects off an underwater reef and is detected by the submarine's receiver exactly 2.4 seconds later. If the speed of sound in seawater is 1500 m/s, how far away is the reef from the submarine?
Science
Gravitation
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by GIANSH GUPTA KHUNDKER
· Class 9
An element has an atomic number of 13 and a mass number of 27. How many neutrons are present in the nucleus of this atom?
Science
Structure of Atom
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by GIANSH GUPTA KHUNDKER
· Class 9
An object of mass 2 kg is sliding with a constant velocity of 4 m/s on a frictionless horizontal table. What is the net force required to keep the object moving with the same velocity?
Science
Force and Laws of Motion
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by GIANSH GUPTA KHUNDKER
· Class 9
The value of the Universal Gravitational Constant (G) was first experimentally determined by:
Science
Gravitation
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by GIANSH GUPTA KHUNDKER
· Class 9
A ball is thrown vertically upwards. At the highest point of its trajectory, its velocity and acceleration are:
Science
Gravitation
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by GIANSH GUPTA KHUNDKER
· Class 9
The gravitational force between two objects depends on the product of their masses and:
Science
Gravitation
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by GIANSH GUPTA KHUNDKER
· Class 9
An object weighs 60 N on Earth. What will be its approximate weight on the Moon?
Science
Gravitation
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by GIANSH GUPTA KHUNDKER
· Class 9
The value of acceleration due to gravity (g):
Science
Gravitation
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