Electricity and Electronics, Exercises of Electrical Engineering

Download Electricity and Electronics and more Exercises Electrical Engineering in PDF only on Docsity! Tutorial Assignment for Lecture 2 [RLC and RLC circuits] READ THE INSTRUCTIONS CAREFULLY BEFORE ATTEMPTING YOUR TUTORIAL ASSIGNMENT. I. For questions with calculated solution, please enter the number according to the required unit. Do not include the SI unit in your answer. II. ALL ANSWERS MUST BE ENTERED ONLINE VIA MOODLE BY THE STATED DEADLINE AT 11:59 P.M. ON 23 SEPTEMBER 2018. III. 4 marks will be awarded for each correct answer and 1 mark will be deducted for each wrong answer. No mark will be deducted for leaving the question unanswered. Q1. By referring to Fig. 1, answer the following questions (round your answer to one decimal point) (1) What are the resistance of R1 and R2 as shown in Fig. 1? Answer: R1 = ( ) Ω Answer: R2 = ( ) Ω (2) What is the equivalent resistance Rs if R1 and R2 are connected in series? Answer: RS = ( ) Ω (3) What is the equivalent resistance Rp if R1 and R2 are connected in parallel? Answer: Rp = ( ) Ω Fig. 1. Diagram depicting two different conductors. ρ1=640Ωm, L1=10 cm d1=4 cm ρ2=0.46Ωm, L2=20 cm d2=2 cm R1 R2 Q2. In Fig. 2, the resistor R1 is connected to a 5 V EMF. Answer the following questions (round your answer to four significant digits) (1) There will be n1×10m1 electrons passing through the cross-section S1 of R1 per second when R1 is connected to the 5 V EMF. What is n1 and m1? (Hint: 1 electron carries −1.602×10-19 C of charge). Answer: n1 = ( ) Answer: m1 = ( ) (2) If the electrons are equally distributed across the cross-sectional area, there will be n2×10m2 electrons passing through the cross-section S2 per second. What is n2 and m2? Answer: n2 = ( ) Answer: m2 = ( ) (3) The battery provides x×10y J of energy to the circuit per second. What is x and y? Answer: x = ( ) Answer: y = ( ) (4) If the circuit works for 1 entire day, how much energy will be consumed by R1 and how many charges are passed through R1? Answer: Energy consumed = ( ) J Answer: Charges = ( ) C ρ1=640Ωm, L1=10 cm d1=4 cm R1 S2 d2=3 cmS1 Fig. 2. A resistive circuit with resistor R1. + 5V R1 Q4. Fig. 4.1 shows a circuit with capacitor C1 at 5 V potential that is connected in series with switch S and capacitor C2 at 0 V potential. When switch S turns on, capacitor C2 is charged by C1 as shown in Fig. 4. 2. After a sufficiently long period, C2 is fully charged and no current flows between C1 and C2 as shown in Fig. 4.3. +5V 1μF 0VC1 C2 S V1+ +V21μF 1μF C1 C2 S + +V21μF 1μF C1 C2 S V1 Fig. 4. 1 Fig. 4.2 Fig. 4.3 (1) For Fig. 4.1, C1 holds a×10b C of charges? What is a and b? Answer: a = ( ) Answer: b = ( ) (2) For Fig. 4.2, C1 and C2 will hold a total of c×10d C of charges? What is c and d? Answer: c = ( ) Answer: d = ( ) (3) For Fig. 4.3, C1 will hold e×10f C of charges and C2 will hold g×10h C of charges? What are the values e, f, g, and h? Answer: e = ( ) Answer: f = ( ) Answer: g = ( ) Answer: h = ( ) (4) What is voltage V1 and V2 as shown in Fig. 4.3? Answer: V1 = ( ) V Answer: V2 = ( ) V Q5. Fig. 5 shows an AC circuit with a voltage source connected in parallel with an inductor and a capacitor. V(t) 1mF 1mH I1(t) + V(t)=10sin(1000t)(V) I2(t) I3(t) Fig. 5. AC circuit with inductor and capacitor. (1) What are the instantaneous current values of I2 and I3 at 𝒕=𝝅/𝟐𝟎𝟎𝟎 and 𝒕=𝝅/𝟏𝟎𝟎𝟎? Answer: 𝐼2(𝑡 = π/2000) = ( ) A Answer: 𝐼2(𝑡 = π/1000) = ( ) A Answer: 𝐼3(𝑡 = π/2000) = ( ) A Answer: 𝐼3(𝑡 = π/1000) = ( ) A (2) What is the energy of the capacitor EC and inductor EL at 𝒕=𝝅/𝟐𝟎𝟎𝟎, respectively? Answer: 𝐸𝐶(𝑡 = π/2000) = ( ) J Answer: 𝐸𝐿(𝑡 = π/2000) = ( ) J (3) What is the energy of the capacitor EC and inductor EL at 𝒕=𝝅/𝟏𝟎𝟎𝟎, respectively? Answer: 𝐸𝐶(𝑡 = π/1000) = ( ) J Answer: 𝐸𝐿(𝑡 = π/1000) = ( ) J (4) What is the total energy of inductor and capacitor ET at 𝒕=𝝅/𝟒𝟎𝟎𝟎, 𝒕=𝝅/𝟐𝟎𝟎𝟎, 𝒕=𝟑𝝅/𝟒𝟎𝟎𝟎 and 𝒕=𝝅/𝟏𝟎𝟎𝟎? Answer: 𝐸𝑇(𝑡 = π/4000) = ( ) J Answer: 𝐸𝑇(𝑡 = π/2000) = ( ) J Answer: 𝐸𝑇(𝑡 = 3π/4000) = ( ) J Answer: 𝐸𝑇(𝑡 = π/1000) = ( ) J Q6. What is the current in the circuit as show in Fig. 6? 15V 5V10V+ + + I1 I2 I3 15Ω 10Ω 5Ω V + V1 - + V2 - + V3 - Fig. 6. Parallel DC circuit. A. I1=0.818 A, I2=1.273 A, I3=0.455A B. I1=-0.818 A, I2=-1.273 A, I3=-0.455A C. I1=-0.455 A, I2=1.273 A, I3=-0.818A D. I1=0.455 A, I2=1.273 A, I3=0.818 A E. I1=1.273 A, I2=0.455 A, I3=-0.818 A F. I1=1.273 A, I2=-0.818 A, I3=-0.455 A Answer: ( ) Q7. What are the voltage and current in the circuit as shown in Fig. 7? Fig. 7. DC circuit with RLC components. A. I=0.3125 A, VL=3.125 V, VC=0.3125 V, VR=1.5625 V B. I=0.3 A, VL=3.5 V, VC=0 V, VR=1.5 V C. I=0.5 A, VL=2.5 V, VC=0 V, VR=2.5 V D. I=1 A, VL=0 V, VC=0 V, VR=5 V E. I=0.833 A, VL=0 V, VC=0.835 V, VR=4.165 V F. I=0 A, VL=0 V, VC=5 V, VR=0 V Answer: ( ) + 5V + VL - + VC - + VR - I 5Ω 1μF 10mH