Study with shahid

 📚 Chapter: Moving Charges and Magnetism – Class 12 Physics Notes --- 🔸 1. Magnetic Force on a Moving Charge When a charged particle moves in a magnetic field, it experiences a force: \vec{F} = q (\vec{v} \times \vec{B}) = qvB \sin\theta Maximum force when  No force when particle is at rest or  --- 🔹 2. Magnetic Force on a Current-Carrying Conductor \vec{F} = I (\vec{L} \times \vec{B}) Direction of force: given by Right-Hand Rule --- 🔹 3. Motion of a Charged Particle in Magnetic Field Path becomes circular if velocity is perpendicular to B. Radius of circular path: r = \frac{mv}{qB} Time period: T = \frac{2\pi m}{qB} --- 🔹 4. Biot–Savart Law Gives magnetic field due to a current element: d\vec{B} = \frac{\mu_0}{4\pi} \frac{I d\vec{l} \times \vec{r}}{r^3} --- 🔹 5. Magnetic Field Due to: Straight wire: B = \frac{\mu_0 I}{2\pi r} Circular loop: B = \frac{\mu_0 I}{2R} \quad \text{(at center)} Solenoid: B = \mu_0 n I --- 🔹 6. Ampere’s Circuital Law \oint \vec{B} \cdot ...

 Chapter: Magnetism and Matter – Class 12 Physics Notes 🔸 Introduction: Magnetism is the phenomenon associated with the motion of electric charges, which gives rise to magnetic fields. This chapter explores bar magnets, Earth's magnetism, magnetic materials, and related laws. --- 🔹 1. The Bar Magnet A bar magnet has two poles: North (N) and South (S). Magnetic field lines emerge from the North pole and enter the South pole. Magnetic field strength is strongest at the poles. Magnetic Moment (M): \vec{M} = m \times 2l  = magnetic pole strength  = length of the magnet Torque on a Bar Magnet in Magnetic Field: \vec{\tau} = \vec{M} \times \vec{B} Potential Energy: U = -\vec{M} \cdot \vec{B} --- 🔹 2. Earth’s Magnetism Earth behaves like a giant bar magnet. The magnetic field of Earth is called geomagnetic field. Important terms: Magnetic Declination (D): Angle between geographic meridian and magnetic meridian. Magnetic Inclination or Dip (I): Angle between Earth's magnetic f...