Transients

A circuit of resistance 10 Ω and inductance 0.1 H in series has a direct voltage of 200 V suddenly applied to it. Find the voltage drop across the inductance at the instant of switching on and at 0.01 second. Find also the flux-linkages at these instants.

Transient disturbance is produced in a circuit whenever 

(a) it is suddenly connected or disconnected from the supply 

(b) it is shorted 

(c) its applied voltage is changed suddenly 

(d) all of the above.

There are no transients in pure resistive circuits because they 

(a) offer high resistance 

(b) obey Ohm’s law 

(c) have no stored energy 

(d) are linear circuits.

The transient current in a loss-free L-C circuit when excited from an ac source is a/ an ….. sine wave. 

(a) over damped 

(b) undamped 

(c) under damped 

(d) critically damped.

Transient current in an R-L-C circuit is oscillatory when 

(a) R = 0 

(b) R  > 2√(L/C)

(c) R  < 2√(L/X)

(d) R = √(L/C) 

Transient currents in electrical circuit are associated with

(a) inductors 

(b) capacitors 

(c) resisters 

(d) both (a) and (b).

The transients which are produced due to sudden but energetic changes from one steady state of a circuit to another are called ……. transients. 

(a) initiation 

(b) transition 

(c) relaxation 

(d) subsidence

Double-energy transients are produced in circuits consisting of 

(a) two or more resistors 

(b) resistance and inductance 

(c) resistance and capacitance 

(d) resistance, inductance and capacitance.

In an R-L circuit connected to an alternating sinusoidal voltage, size of transient current primarily depends on 

(a) the instant in the voltage cycle at which circuit is closed 

(b) the peak value of steady-state current 

(c) the circuit impedance 

(d) the voltage frequency.

A 50-Hz sinusoidal voltage of maximum value of 400 V is applied to a series circuit of resistance 10 Ω and inductance 0.1 H. Find tan expression for the value of the current at any instant after the voltage is applied, assuming that voltage is zero at the instant of application. Calculate its value 0.02 second after switching on