MGVCL Exam Paper (30-07-2021 Shift 3)
A conductor having surface density is embedded in a dielectric medium of permittivity. The electric field in the medium is E. If it is known that the pressure p on the conductor surface is equal to the electric energy density in the medium, then p (in SI unit)is given by
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.
Buchholz relay is used for protecting transformer against incipient or internal faults. Buchholz relay is a gas-actuated relay installed in oil immersed transformers for protection against all kinds of faults.
Value of power factor is varies from 0 to 1. R→PF = 1 L→PF = 0 lag C→PF = 0 lead R-L→0 lag < PF < 1 R-C→0 lead < PF < 1 R-C-L→depends on value of R, L and C. PF = R/Z
EXAMIANS