Doubtify – JEE Ki Taiyaari, Simple Bhasha Mein

  ❓ Concept 🎬 Charged Particle in Magnetic Field — r vs E Graph in 59 Sec Charged particle magnetic field mein gaya… energy badhi … par sawal yeh hai 👇 👉 radius linearly badhega ya curve banayega? ⚡🤔 Is concept ko pakad liya, toh graph-based magnetism questions JEE mein free ho jaate hain 🔥 🖼️ Concept Image ✍️ Short Explanation Yeh question calculation ka nahi , relation samajhne ka test hai. Bas teen steps yaad rakho — force → speed → energy . 🔹 Step 1 — Magnetic Force Causes Circular Motion (FOUNDATION 💯)** Jab charged particle ki velocity magnetic field ke perpendicular hoti hai: q v B = m v 2 r qvB=\frac{mv^2}{r} 👉 Magnetic force centripetal force ka kaam karta hai aur particle circular path follow karta hai. 🔹 Step 2 — Radius Depends on Speed Upar wale relation se: r = m v q B r=\frac{mv}{qB} So: r ∝ v \boxed{r\propto v} 📌 Intuition: Zyada speed ⇒ magnetic field ke liye bend karna mushkil Result ⇒ larger radius 🔹 Step 3 — ...

❓ Question A particle of charge q q q , mass m m m and kinetic energy E E E enters a uniform magnetic field perpendicular to its velocity and undergoes a circular arc of radius r r r . Which of the following curves correctly represents the variation of r r r with E E E ? 🖼️ Question Image ✍️ Short Explanation This is a pure relation-based magnetism question . No numbers. No tricks. 👉 Sirf radius–energy dependence samajhni hai. 🔹 Step 1 — Magnetic force causes circular motion For a charged particle moving perpendicular to magnetic field B B B : q v B = m v 2 r So radius of circular path: r = m v q B 📌 Radius speed v v v par depend karta hai. 🔹 Step 2 — Connect speed with kinetic energy Kinetic energy: E = 1 2 m v 2 So: v = 2 E m v=\sqrt{\frac{2E}{m}} ​ Substitute in radius expression: r = m q B 2 E m r=\frac{m}{qB}\sqrt{\frac{2E}{m}} Hence: r ∝ E \boxed{r\propto \sqrt{E}} ​ ​ 🔹 Step 3 — Nature of r vs E graph (MOST IMPORTANT 🔥)** From: r ∝ E r\pro...

  ❓ Concept 🎬 Motion of Charge at Boundary of Two Magnetic Fields — Concept in 59 Sec Ek charged particle uniform magnetic field mein gaya — 👉 circular motion start 🔄 Par jaise hi particle boundary cross karta hai aur magnetic field change hoti hai, 👉 radius bhi change ho jaata hai! Ab sawal yeh hota hai: Net displacement kaise aur kyun aata hai? 🔥 🖼️ Concept Image ✍️ Short Explanation Yeh question formula-based nahi , pure concept + geometry ka test hota hai. Agar tum radius–bending logic samajh gaye, toh answer automatically build ho jaata hai 😎 🔹 Step 1 — Magnetic Force = Circular Motion (FOUNDATION 💯)** Jab charge q q , speed v v  ke saath magnetic field B B  ke perpendicular move kare: q v B = m v 2 r qvB = \frac{mv^2}{r} So radius: r = m v q B r=\frac{mv}{qB} 📌 Direct observations : B B  ↑ ⇒ r r  ↓ (particle zyada bend karega) B B  ↓ ⇒ r r  ↑ (particle kam bend karega) 🔹 Step 2 — Two Regions = ...