1:22 PM 117 K/S AC UNIVERSITY OF ABUJA FACULTY OF ENGINEERING DEPARTMENT OF ELECTRICAL AND ELECTRONIC ENGINEERING SECOND SEMESTER EXAMINATION, 2022/2023 SESSION Programme: Degree Course Title:Basic electrical Engineering (II) Course Code: EEE 229. Instruction: Answer FOUR Questions Only Question One Time Allowed: 2 Hours Units: 2 a. Define the following terms: Active power, reactive power, and apparent power.[6 marks] h. In a circuit the equations for instantaneous voltage and current are given by v = 141.4 sin (wt- 2), volt and i = 7.07 sin (wt), amp, where w=314 rad/sec. (i) Sketch a neat phasor diagram for the circuit. (ii)Use polar notation to calculate impedance with phase angle (iii) Calculate average power and power factor (iv) Calculate instantaneous power at the instant t0.[11.5 marks] Question Two a. (i) What is an ideal transformer?[2.5 marks] (ii) List two (2) types of transformers.[2 marks] b. Explain why transformers are rated in volt-amperes (VA ar KVA or MVA). [3 marks] The maximum flux density in the core of a 250/3000V, 50Hz, single phase transformer is 1.2Wb/m². If the emf per turn is 8V. Determine: (i) primary turns (ii) secondary turns (iii) area of the core [10 marks] Question Three a. b. State Thevenin and Norton theorem; also draw their equivalent circuit diagram in sinusoids.[7.5 marks] Find the Thevenin equivalent at terminals a-b of the circuit shown below 60 25 100/20° VI -j40 1052 Question Four a. Explain the terms: Admittance, Conductance and Susceptance.[6 marks] [10 marks] The impedance of two circuits connected in parallel are given as 2, 15+112 and 2-8- 15 ohm. If the potential difference across one of the impedance is 250 V. Calculate (1) total current and branch currents, (ii) total power and power consumed in each branch and (iii) overall power factor and power factor of each branch.[11.5 marks] ||| O כ Մ 1:23 PM < second semester...t questions.pdf Phoenix Files 100/20° ± -j4n 1052 Explain the terms: Admittance, Conductance and Susceptance.[6 marks] Question Four a. K/S AC [10 marks] The impedance of two circuits connected in parallel are given as Z, 15+112 and 2, -8- 15 ohm. If the potential difference across one of the impedance is 250 V. Calculate (i) total current and branch currents, (ii) total power and power consumed in each branch and (iii) overall power factor and power factor of each branch.[11.5 marks] Question Five a. Define a source free RC circuit.[2 marks] b. For a source-free RC circuit shown in Figure 1, prove that v(t)e" c. In figure 2 below let (0) 15V. Find P. V, and i, for >0. Question Six Sa 17 marks] [8.5 marks] 12 a. Explain a logic circuit?[2.5 marks] b. Multiply the decimal numbers 50 and 20 by binary means.[3 marks] c. Draw the logic gate symbols and truth tables for a three (3) inputs of OR, AND, & NOR gates. [12 marks] Rotate = |||| Q Search n о D Share