Question

Find the magnitude of the electric field just above the middle of a large, flat, horizontal metal sheet carrying a charge density of 90 nC/m².

Answer 1

k = 1, σ = 90 nC/m² = 90 × 10^-9 C/m²,

ε₀ = 8.85 × 10^-12 F/M

The required electric field, E `σ/(2kε_0)`

= `(90 xx 10^-9)/(2(1)(8.85 xx 10^-12))`

= `45/8.85 xx10^3`

log 45 =        1.6532
log 8.85 = − 0. 9469
                     0.7063

AL(0.7063) = 5.086

= 5.086 × 10³ N/C