HW1

ENGR 205, Spring 2012 [Homework 1 (Chapter 1)]

Dr. Fahad Alajmi page 1

Problems that indicate ‘*’ must be submitted

*P1.1

The current that enters an element is shown in Figure 1. ‎‎Find the charge that enters

the element in the time interval 0 < t < 20s.

*P1.2

The power absorbed by the box in figure 2 is W. Calculate the amount of charge

that enters the box between 0.1 and 0.4 seconds

Figure 2

P1.3

The power absorbed by the box in figure 3 is W. Calculate the energy absorbed

by the box between 0.1 and 0.4 seconds.

Figure 3

.

Figure 1



P1.4

The energy absorbed by the box in Figure 4 is given below. Calculate and sketch the

current flowing in to the box. Also calculate the charge which enters the box between 0

and 12 seconds.

.

Figure 4

P1.5

Determine the amount of power absorbed or supplied by the element in figure 5 if

(a) V1 = 9V and I = 2A

(b) V1 = 9V and I = -3A

(c) V1 = -12 V and I = 2A

(d) V1 = -12V and I = -3A

Figure 5



*P1.6

Find the power absorbed by each element in figure 6

Figure 6

P1.7

Element A in the diagram in figure 7 absorbs 30 W of power. Calculate Vx.

Figure 7

*P1.8

Figure 8 shows a circuit with five elements. If P1 = -205 W, P2 = 60 W, P4 = 45 W, P5

= 30 W, Calculate the power P3 received or delivered by element 3.

Figure 8



*P1.9

Figure 9 shows direction of current through and voltage across an element. The current

and voltage versus time are shown below.

(a) Sketch the power p(t) dissipated in the element.

(b) Find the total energy absorbed by the element for the time period

Figure 9

*P1.10

(a) In figure 10 (a) P1 = 36 W. Is element 2 absorbing or supplying power, and how

much?

(b) In Figure 10 (b) P2 = -48 W. Is element 1 absorbing or supplying power, and how

much?

Figure 10

1.10(a)



*P1.11

In the circuit in figure 12, element 1 absorbs 40 W, element 2 supplies 50 W, element 3

Supplies 25 W, and element 4 absorbs 15 W. How much power is supplied by element 5?

Figure 11

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HW1