JEE Main: Separated Lenses Power Formula 💡
❓ Question How do we calculate the equivalent power when two thin lenses are placed at a distance from each other? 🖼 Concept Image ✍️ Short Concept This is a lens combination formula-based question. Golden idea: 👉 Touching lenses → simple addition 👉 Separated lenses → correction term aata hai 🔷 Step 1 — Power of a Lens 💯 P = 1 f P = \frac{1}{f} (f in metres ) Convex lens → positive power Concave lens → negative power 🔷 Step 2 — When Lenses Are Touching If lenses are in contact: P t o t a l = P 1 + P 2 \boxed{P_{total} = P_1 + P_2} 👉 Bas simple addition. No extra term. 🔷 Step 3 — When Lenses Are Separated (MOST IMPORTANT) If separation distance = d: P t o t a l = P 1 + P 2 − d P 1 P 2 \boxed{P_{total} = P_1 + P_2 - d P_1 P_2} ⚠️ Distance term always minus ⚠️ d must be in metres Yahin JEE trap lagata hai. 🔷 Step 4 — Why Distance Matters? First lens image banata hai. Wahi image second lens ke liye object ban jata hai. Isliye system simple ad...