4.1The current through a branch in a linear network is 2 A when the input source voltage is 10 V. If the voltage is reduced to 1 V and the polarity is reversed, the current through the branch is:
(b) −0.2
4.2For superposition, it is not required that only one independent source be considered at a time; any number of independent sources may be considered simultaneously.
(a) True
4.3The superposition principle applies to power calculation.
(b) False
4.4Refer to Fig. 4.67. The Thevenin resistance at terminals a and b is:
(d) 4Ω
4.5The Thevenin voltage across terminals a and b of the circuit in Fig. 4.67 is:
(b) 40 V
4.6The Norton current at terminals a and b of the circuit in Fig. 4.67 is:
(a) 10 A
4.7The Norton resistance RN is exactly equal to the Thevenin resistance RTh.
(a) True
4.8Which pair of circuits in Fig. 4.68 are equivalent?
(c) a and c
4.9A load is connected to a network. At the terminals to which the load is connected, RTh = 10 Ohmand VTh = 40 V. The maximum power supplied to the load is:
(c) 40 W
4.10The source is supplying the maximum power to the load when the load resistance equals the source resistance.
7.1An RC circuit has R = 2 Ωand C = 4 F. The time constant is:
(d) 8 s
7.2The time constant for an RL circuit with R = 2 Ωand L = 4 H is:
(b) 2 s
7.3A capacitor in an RC circuit with R = 2 Ω and C = 4 F is being charged. The time required for the capacitor voltage to reach 63.2 percent of its steady-state value is:
(c) 8 s
7.4An RL circuit has R = 2 Ω and L = 4 H. The time needed for the inductor current to reach 40 percent of its steady-state value is:
(b) 1 s
7.5In the circuit of Fig. 7.79, the capacitor voltage just before t = 0 is:
(d) 4 V
7.6In the circuit of Fig. 7.79, v(∞) is:
(a) 10 V
7.7For the circuit of Fig. 7.80, the inductor current just before t = 0 is:
(c) 4 A
7.8In the circuit of Fig. 7.80, i(∞) is:
(e) 0 A
7.9If vs changes from 2 V to 4 V at t = 0, we may express vs as:
(c) 2u(−t) + 4u(t) V
(d) 2 + 2u(t) V
7.10The pulse in Fig. 7.110(a) can be expressed in terms of singularity functions as: