MGVCL Exam Paper (30-07-2021 Shift 3)
If the phase velocity of a plane wave in a perfect dielectric is 0.4 times its value in free space, then what is the relative permittivity of the dielectric?
When voltage changes occur in rapid succession, with magnitudes large enough to cause lighting level variations. The human eye-brain response is most sensitive to periodic r.m.s. voltage changes that occur at around 8 - 10 cycles per second.