Latent heat of fusion is defined as the heat required to: MCQ with Answer and Explanation

Explanation:
NPK fertilizers supply the three primary macronutrients: Nitrogen (N), Phosphorus (P), and Potassium (K). Plants also require trace elements (micronutrients) in very small amounts for proper growth, such as Iron, Manganese, Zinc, Copper, Boron, and Molybdenum. Both statements are factually correct.

Explanation:
Electronegativity is the tendency of an atom to attract shared electrons in a chemical bond. It increases across a period and decreases down a group. Fluorine, located at the top right of the periodic table (Group 17, Period 2), has the smallest atomic radius and highest effective nuclear charge, giving it the highest electronegativity (3.98 on Pauling scale).

Explanation:
Polyethylene (polythene) softens on heating and hardens on cooling, so it is thermoplastic. Bakelite is thermosetting; rubber is elastomer; silk is natural polymer.