Show that an intensity of 1012 W/m2 is the same as 1016 W/cm2 .
Physics 2 for Engineering Week 3 September 18 24 th th Metal sphere = conductor Charge comes to the surface Surface charge σ = Q / A Insulator Charge distributed over the volume ρ = Q / V Gauss’s Law Charges inside closed surfaces (Q = enclosed charge) ϕ is electric flux (electric field and area product with units N*m /C) 2 ϕ = E * A = Q / Ɛ 0 Gaussian surface must be symmetric For point or sphere charges, Gaussian surface has a spherical distribution For linear or sheet charges, Gaussian surface has a cylindrical distribution For a conducting sphere on the circumference E = q / (4πƐ R ) 0 2 Eon the inside of a conducting sphere = 0 λ = Q / L (charge per unit length) For a long wire E = λ / (2πrƐ ) 0 For a cylinder E = q / (2πrLƐ ) 0 For an infinitely thin sheet E = σ / 2Ɛ 0 For an infinitely large object (with thickness) E = σ / Ɛ 0