Department of Electrical &Computer Engineering,
School of Engineering& Digital Sciences
ELCE 200 Circuit Theory I (Fall 2021)
Teachers: Akhan Almagambetov & Galymzhan Nauryzbayev
Take-home Assignment # 1
Topics: Charge and Current; Voltage, Power and Energy;
Passive Sign Convention Ohm's Law; Power; Resistance
[CLO1]
[Max. Points: 50]
[Dated: 18-08-2021]
[Deadline: 25-08-2021]
Please read the following important notes very carefully:
1. Follow the Homework Formatting Guidelines posted on Moodle.
2. Use the provided paper template to prepare your solution.
3. Make clear sketches with proper scale and clear labeling, where necessary.
4. Please convert the completed-assignment file to PDF and rename the file as
HW01_LastName_FirstName.pdf
For example,
HW01_Smith_Aaron.pdf
5. The submission link will be provided over Moodle.
6. The submitted assignment must be your own work.
Good Luck!!!
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Page 1 of 3
1.
The charge entering a certain element is shown in Figure 1. Find the current at:
(a) t = 2 ms;
(b) t = 8 ms;
(c) t = 12 ms.
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Figure 1.
2.
3.
4.
5.
Figure 2 plots the charge flowing in a wire. Sketch the corresponding current.
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Figure 2.
A rechargeable flashlight battery is capable of delivering 50 mA for about 6 h. How much
charge can it release at that rate? If its terminal voltage is 3 V, how much energy can the
battery deliver?
The current through and the voltage across an element are given in Figure 3 below.
(a) plot the power delivered to the element for 𝑡 > 0;
(b) calculate the energy absorbed by the element in the time interval 0 ≤ 𝑡 ≤ 2 s.
Figure 3.
The current entering the positive terminal of a device is 𝑖(𝑡) = 6𝑒 −2𝑡 mA and the voltage
across the device is 𝑣(𝑡) = 10𝑑𝑖/𝑑𝑡 V.
(a) Find the charge delivered to the device between 𝑡 = 0 and 𝑡 = 3 s;
(b) Calculate the power absorbed;
(c) Determine the energy absorbed in 3 s.
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Page 2 of 3
6.
7.
8.
Figure 4 shows a circuit with four elements, 𝑝1 = 60 W absorbed, 𝑝2 = −145 W
absorbed, and 𝑝3 = 75 W absorbed. How many watts does Element 4 absorb?
Figure 4.
Find the power absorbed by each element depicted in Figure 5.
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Figure 5.
A bar of silicon, with a resistivity of 640 Ω-m, is 4 cm long with a circular cross section. If
the resistance of the bar is 240 Ω at a room temperature, what is the cross-sectional radius
of the bar?
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9.
Find the hot resistance of a light bulb rated 90 W, 120 V.
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10.
Figure 6 shows the power consumption of a certain household in 1 day. Calculate:
(a) the total energy consumed in kWh;
(b) the average power over the total 24 hour period.
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Figure 6.
Page 3 of 3