In a typical cloud-to-ground stroke (R stroke), negative electric charge (electrons) of the order of Q ≈ 1 C stored within the lightning channel is lowered to the ground within a typical impulse time interval of τ = 100 μs. This corresponds to an average current flowing within the channel of the order of J ≈ Q ⁄ τ = 10 kA. Maximum spectral energy is generated near frequencies of f ≈ 1 ⁄ τ = 10 kHz, or at wavelengths of λ = c ⁄ f ≈ 30 km (where c is the speed of light). In typical intracloud K-strokes, positive electric charge of the order of Q ≈ 10 mC in the upper part of the channel and an equivalent amount of negative charge in its lower part neutralize within a typical time interval of τ ≈ 25 μs. The corresponding values for average electric current, frequency and wavelength are J ≈ 400 A, f ≈ 40 kHz, and λ ≈ 7.5 km. The energy of K-strokes is in general two orders of magnitude weaker than the energy of R-strokes.