University:
Santa Fe College
Course:
PHY 2004 | Applied Physics 1
Academic year:

2024
Views:

101

Pages:

5
Author:

Jabin F.

Current Outside The Wire Ienc = ∫∫S J ds Ienc = ∫(0 to 2π)∫(0 to a) (J0(a²-r²)/a²) r dr dφ Ienc = (2πJ0/a²) ∫(0 to a) (a²r/2 - r³/3) dr Ienc = (2πJ0a²/4) = (πJ0a²/2) Ienc = (πJ0a²/2) Total current in the wire. ∮B.dl = μ0Ienc Bout 2πr = μ0(πJ0a²/2) Bout = (μ0J0a²/2) / (2πr) Bout ∝ 1/r Q.82 Let E(x,y,z,t) = E₀cos(2x+3y-ωt) be the electric field of an electromagnetic wave traveling in vacuum. Which of the following vectors is a valid choice for E₀? (NET Nov. 26, 200) (a) (î - ĵ)/√2 (b) (î + ĵ)/√2 (c) (î + ĵ)/√2 (d) (î - ĵ)/√2 Sol: k = (2î + 3ĵ) For vacuum: k.E₀ = 0 (a) 2 - 3 ≠ 0 (b) 2 + 3 ≠ 0 (c) 2 + 3 ≠ 0 (d) 2 - 3 = 0 Q.42 Page 7.55 Page 7.56 σ = 10⁻⁴ S/m ε = 80ε₀ R = 10⁶ Ω Time Constant (τ) = RC = σ/ε ⇒ τ = εR/σ = 10^-4 / (80 * 8.85 * 10^-12 * 70^6) => C = ε / σR = (80 * 8.85 * 10^-12) / (10^6 * 10^-4) = 7.08 x 10^-12 F = 7.08 pF