This post is the answers and detailed explanations companion to our earlier practice set titled “NEET UG 2026: If You Solve These Problems, You Will Get 90+ Percentile for Sure.” If you haven’t attempted those questions yet, we strongly recommend trying them first before jumping into the solutions. The previous post is designed to test your exam-level preparation, while this one will help you understand every concept behind the correct answers, clear your doubts, and strengthen your problem-solving approach for NEET UG 2026.
Answers and Explanations
Ans 1. A – Increases linearly with distance from centre
Explanation:
Inside a uniformly dense sphere, only the mass enclosed within radius r contributes to gravity. Since the enclosed mass ∝ r^3 (r cube), gravitational force becomes proportional to r. Hence, the force increases linearly with distance from the centre.
Ans 2. C – Zero
Join NEET News 2025 Explanation:
Since the block moves with constant speed, its kinetic energy does not change. By the work–energy theorem, net work done equals change in kinetic energy, which is zero. Hence, the net work done by all forces is zero.
Ans 3. D. Accelerating downward
Explanation:
The weighing scale reads the normal reaction. When the lift accelerates downward, N = m(g – a), which is less than mg. Hence, the scale reading decreases, indicating downward acceleration.
Ans 4. A – Mitochondria are present in all prokaryotic and eukaryotic cells.
Explanation:
Mitochondria are absent in prokaryotic cells and also absent in mammalian RBCs. They are present only in eukaryotic cells that require energy for metabolism. All the other statements are correct.
Ans 5. D – A is false, but R is true
Explanation:
Salivary amylase does not digest proteins; it acts on starch (a carbohydrate) and converts it into maltose. Protein digestion begins in the stomach by pepsin, not in the mouth.
Ans 6. D – Endothelium is a part of the tunica media.
Explanation:
The endothelium is a part of the tunica intima, not the tunica media. Tunica media consists mainly of smooth muscle, while tunica externa is the outermost layer of the artery.
Ans 7. C – NADPH is produced along with ATP
Explanation:
In non-cyclic photophosphorylation, light energy drives the flow of electrons from water to NADP⁺, forming NADPH, and also generates ATP. Oxygen is released as a byproduct, and electrons do not return to the same chlorophyll.
Ans 8. A – Both A and R are true, and R is the correct explanation of A
Explanation:
The corpus luteum secretes progesterone during the luteal phase, and this hormone prepares the endometrium for implantation of the embryo. Hence, the reason correctly explains the assertion.
Ans 9. C – A is false, but R is true.
Explanation:
Test cross involves crossing an unknown genotype with a homozygous recessive individual (not dominant), and this is indeed done to determine if the unknown is heterozygous or homozygous by observing offspring phenotypes, as stated in Reason (R).
Ans 10. C – Real gases deviate from ideal behaviour due to intermolecular forces.
Explanation:
Real gases show deviation from ideal behaviour because intermolecular attractions and the finite volume of molecules become significant, especially at high pressure and low temperature.
Ans 11. A – Both A and R are true, and R is the correct explanation of A
Explanation:
Across a period, the effective nuclear charge increases, which results in a stronger attraction between the nucleus and the valence electron. Hence, more energy is required to remove an electron, so ionization enthalpy increases.
Ans 12. A- Both A and R are true, and R is the correct explanation of A
Explanation:
Tertiary carbocations are more stable because they have maximum hyperconjugation and strong +I (electron-releasing) effect from three alkyl groups, which stabilizes the positive charge.
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