University:
Kentucky State University
Course:
PHY 212 | General Physics II
Academic year:

2024
Views:

314

Pages:

22
Author:

shinsino45r

**Ch 28: Magnetic Fields:** Magnets: Materials have the ability to attract magnetic objects. Types of magnets: - Permanent magnets (Natural) - Electromagnets **Definition of Magnetic Field B** **F = qv x B** [Image of a vector cross product] **F = qvB sinθ** **B = F / qv sinθ** [B] = N / (C * (m/s)) = Tesla = T 1 T = 10^4 gauss **Magnitude = qvB sinθ** **Direction (R.H.R)** **Example:** A charge is moving in the positive x-axis in a region of B in the positive y-axis. Determine the direction of F? **F = qv x B** [Image of a coordinate system with vectors V, B, and F] **F → +z-axis** out of the page **Example:** v → y-axis B → -z-axis F → +x-axis (the charge) **Ex: A proton and electron are moving with same speed in a region of magnetic field. Determine the particles using figure "1".** [Image of a diagram showing a proton and electron moving in a magnetic field] mp > me Vp = Ve qp = +e qe = -e Bp = Be r ∝ m => r₁ > r₂ v₁ = v₂ mp > me Then the direction of B: B = (-z-axis) **Periods: T** v = distance / time = 2πr / T T = 2πr / v = 2π * mv / qB = 2πm / qB ⇒ Frequency: f = 1/T = qB / 2πm **Angular speed (Angular frequency)** ω = Δθ/Δt = 2π/T = 2πf = 2π(qB/2πm) = qB/m **P24 Page 759:** B = 4 mT proton or electron F = 3.2 x 10^-15 N v = 22 F = qv x B = qvB sin90° 3.2 x 10^-15 = 1.6 x 10^-19 x v x 4 x 10^-3 v = 5 x 10^6 m/s [Image of a circular path with a particle moving in a magnetic field]