Q2: Select the right answer for the following: 1- the equivalent resistance of the circuit given in fig.1 between A and B, is ---. (A) (B) 5 (C) 1 (D)15 Fig.1 202 40 2- A heater takes a current of 8 A from a 230 V source for 12 h. Calculate the energy consumed in kilowatt hours. (A) 220 kw.h (B) 2.2 kw.h (C) 22 kw.h (D) 2 kw.h 202 3- Three similar primary cells are connected in series to form a closed circuit as shown in Fig. 2. Each cell has an e.m.f. of 1.5 V and an internal resistance of 30 2. Calculate the current. (A) 0.05 A (B) 0.5 A (C) 0.05 A (D) 45 A R-302 E=1.5V E-1.5V R-30 Fig.2 2-300 B E-1.5V 4- An alternating voltage has the equation v=141.4 sin 377t; what are the values of: (i) r.m.s. voltage; (ii) frequency; (iii) the instantaneous voltage when t = 3 ms? (r. m. s. = 10 V A) f = 50 Hz vi = 127.8 V (r. m. s. = 90 V C) f = 60 Hz vi = 127.8 V B) (r. m. s. = 90 V f = 50 Hz 5- For the air-core coil in Fig. 3: Find the inductance. (A)15.68µH (B) 20 μH (C) 10 μH (D) 1.5 μH Fig.3 Page 2 of 4 vi = 127.8 V (r. m. s. = 100 V D) f = 60 Hz vi = 127.8 V 1-25.4mm Air core () d=6.35mm 100 turns