The number of protons in an atom determines its MCQ with Answer and Explanation

Explanation:
When a body is lifted against gravity, work done (mgh) is stored as gravitational potential energy. This energy can be recovered when the body falls. Kinetic energy relates to motion, thermal to heat, elastic to deformed materials. The conservation of energy principle states that work done against conservative forces becomes potential energy. Formula: PE = mgh, where h is height above reference. Memory aid: 'Potential' means stored energy due to position. This conceptual question tests energy transformation understanding, frequently appearing in work-energy theorem applications in competitive exams.

Explanation:
Fission: heavy nucleus (e.g., U-235) splits into smaller nuclei plus neutrons and energy. Fusion: light nuclei combine (e.g., hydrogen to helium). Both release energy. Fission used in reactors and bombs.

Explanation:
Astigmatism: cornea curvature not spherical, different focal lengths in different planes. Corrected by cylindrical lens which has different powers in perpendicular axes. Not simple spherical lens.