Doubtify – JEE Ki Taiyaari, Simple Bhasha Mein

  ❓ Concept 🎬 Electrostatics — Potential Energy is Path Independent (59 Sec) Charge circular path pe move kare, curve dikhe, arc dikhe… 👉 Par JEE poochta hai sirf start aur end ka khel! ⚡🧠 Electrostatics ka yeh golden rule pakad liya, toh half chapter khud simplify ho jaata hai 🔥 🖼️ Concept Image ✍️ Short Explanation Electrostatic force conservative hoti hai. Matlab energy change path pe depend nahi karta . Isliye circular path sirf distraction hai 😎 🔹 Step 1 — Key Rule: Electrostatic Force is Conservative (FOUNDATION 💯)** Electrostatic field ka sabse powerful rule: Δ U = U f − U i \Delta U = U_f - U_i 👉 Depends only on: Initial position Final position ❌ Path does NOT matter Circular, zig-zag, straight — sab same. 🔹 Step 2 — Potential Energy Change Formula For a charge q 3 q_3 ​ placed in electric field: Δ U = q 3 ( V f − V i ) \Delta U = q_3 (V_f - V_i) ⚡ Sirf potential difference important hai. Force ka work = potential energy change...

  ❓ Question Two charges q 1 q_1 ​ and q 2 q_2 ​ are separated by a distance of 30 cm . A third charge q 3 q_3 ​ , initially at C (as shown), is moved along a circular path of radius 40 cm from C to D . If the change in potential energy of q 3 q_3 ​ due to this movement is q 3 K 4 π ε 0 , \frac{q_3 K}{4\pi\varepsilon_0}, find the value of K K . 🖼️ Question Image ✍️ Short Solution This is a pure potential-energy difference problem . 👉 Path does NOT matter — only initial and final positions matter. We compare the electric potential at C and D due to fixed charges q 1 , q 2 q_1, q_2 . 🔹 Step 1 — Understand the Geometry (MOST IMPORTANT 💯)** From the figure: q 1 q_1 ​ at point A q 2 q_2 ​ at point B A B = 30  cm AB = 30\text{ cm} A C = 40  cm AC = 40\text{ cm}  (vertical) Arc CD is a quarter circle of radius 40 cm , centred at A So: A D = 40  cm AD = 40\text{ cm} B D = A D − A B = 40 − 30 = 10  cm BD = AD - ...