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4. (a) A resistor network is shown in Figure 4a). By applying the Kirchhoff's (6 marks) current law, determine the value of the currents Ii, 13 and 14. 14 13 17=100A Is =50A W 12=30A ww 16 =20A Figure 4(a) (b) As shown in Figure 4(b), a series RLC circuit is connected to a 50 V 50 Hz AC supply. The circuit consists of a 20 S2 resistor, a 25 mH inductor, and a 200 uF capacitor. (1) Determine the total impedance (Z) in rectangular form. (3 marks) (ii) Calculate the supply current (I) in polar form; and (2 marks) (iii) Calculate the voltages across the resistor (VR), inductor (VL), and capacitor (3 marks) (Vc) in polar form. (iv) Sketch a phasor diagram to show the supply current (1), supply voltage (V), (5 marks) and voltages across the resistor (VR), inductor (VL), and capacitor (Vc). 50 V, 50 Hz R L с Figure 4(b) (c) A student is doing a test for the LRC circuit similar with connection shown (6 marks) in Figure 4(b). He takes a resistor with a low resistance value. Then, he randomly picks an inductor and capacitor. At last, he connects a 220 V a.c. to all of them in series. However, it is found that the protection fuse of the circuit is blown. Identify the possible problem with explanation.