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#1
By Zain
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Medium
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Fact Checked
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06 Mar 2026
Where in the chloroplast do the light-independent reactions (Calvin cycle) of photosynthesis occur?
💡 Explanation:The light-independent reactions, also known as the Calvin cycle, take place in the stroma, which is the fluid-filled space surrounding the thylakoids within the chloroplast.
#2
By Zain
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Medium
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Fact Checked
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04 Mar 2026
How does a catalyst primarily increase the rate of a chemical reaction?
💡 Explanation:A catalyst functions by providing an alternative reaction pathway with a lower activation energy. This allows a greater fraction of collisions between molecules to result in a reaction without the catalyst being consumed.
#3
By Zain
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Hard
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Fact Checked
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04 Mar 2026
Why does the temperature of a gas decrease when it undergoes sudden expansion in a perfectly insulated container?
💡 Explanation:In an adiabatic process (no heat exchange), the First Law of Thermodynamics states that the work done by the gas during expansion comes from its internal energy. As internal energy decreases, the temperature falls.
#4
By Zain
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Medium
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Fact Checked
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23 Feb 2026
If a car rounds a curve at double its original speed, the centripetal force required to keep it on its path will:
💡 Explanation:The formula for centripetal force is F = mv^2 / r. Since force is proportional to the square of the velocity, doubling the speed (2v) results in 2 squared, which is 4 times the original force.
#5
By Zain
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Medium
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Fact Checked
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23 Feb 2026
The greenhouse effect occurs because certain atmospheric gases are:
💡 Explanation:Greenhouse gases allow high-energy, short-wave solar radiation to reach Earth but trap low-energy, long-wave infrared radiation (heat) emitted from the surface.
#6
By Zain
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Medium
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Fact Checked
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22 Feb 2026
What element possesses the highest electronegativity on the Pauling scale?
💡 Explanation:Fluorine is the most electronegative element with a value of 3.98, meaning it has the strongest tendency to attract shared electrons in a chemical bond.
#7
By Zain
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Medium
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Fact Checked
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22 Feb 2026
Which physical property primarily determines a star’s lifecycle, luminosity, and eventual fate?
💡 Explanation:A star's initial mass is the most critical factor in its evolution; it determines the core pressure, the rate of nuclear fusion, and whether the star will end as a white dwarf, neutron star, or black hole.
#8
By Zain
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Medium
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Fact Checked
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14 Feb 2026
If voltage across a resistor is doubled and resistance is halved, what happens to the electric current?
💡 Explanation:According to Ohm's Law, I = V/R, where I is current, V is voltage, and R is resistance. If the voltage (V) is doubled (2V) and the resistance (R) is halved (R/2), the new current (I') is calculated as: I' = (2V) / (R/2) = 4(V/R) = 4I. Therefore, the current quadruples.
#9
By Zain
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Hard
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Fact Checked
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13 Feb 2026
Which discontinuity marks the primary boundary between the Earth’s lower mantle and outer core?
💡 Explanation:The Gutenberg Discontinuity, also known as the Core-Mantle Boundary (CMB), is located at a depth of approximately 2,900 km and separates the solid lower mantle from the liquid outer core. The sudden disappearance of seismic S-waves at this depth is the primary evidence for the liquid state of the outer core.
#10
By Zain
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Medium
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Fact Checked
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13 Feb 2026
Which subatomic particle primarily determines an element’s chemical properties?
💡 Explanation:The chemical properties of an element, such as its reactivity and ability to form bonds, are determined by the configuration of its electrons, particularly the valence electrons in the outermost shell.
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