Question

(3) A step down transformer with 1022 V in the primary circuit has a ratio of primary to secondary windings equal 7. The effective load of the secondary circuit equals 5.3 2. Determine the effective resistance (22) of the primary circuit. (a) 260. (b) 146. (c) 580. (d) 435. (e) 1305 (1) 640. (g) 1022 (4) You are speeding north on a new Harley Davidson V-rod Muscle motorcycle at the insane speed of 55.0 m/s and note an ambulance behind you also moving north at 33.0 m/s. If the siren pitch of the ambulance corresponds to 845 Hz, what frequency (Hz) do you hear? The speed of sound is 330 m/s. The V-rod motorcycle claims a top speed of 61 m/s (137 mph). Choice Choice (a) 825 (e) 782 (b) 1095 (1) 954 797 (g) 896 (d) 640

Answer 1

Aus Relation lelko Primary current (Ip), secondary surrent (Is), Primary no. of coils up, secondary number of coils ng is me » IPT (M) H os Rs (Resistance in secondary & Ip = Esi ( Bons) and also we know & a no 9 Is Ep Los) m) » Ip = Ep de fotos) 3) Ip = E , where Rp = Rs ( up 12 & Rp = 513 (7) 2 = 259,72 [ Rs = 5.32 8 ne-77 = ms so answer is 26002 option las given Aus Doppler's formada for sound is given day, v'= 18-4 & us where D'is frequency of sound heard by Listener & is original frequency (>= 845 H2 given). Vis velocity of sound in air (v = 330 m/sec). I is speed of listener (19 = 55 m/h) Us is speed of source (Ų = 33m/sec) 297 2 = 330-55x845 = 275 x 845 = 782-4 Hz 330-33 So, answer is 782 H2 option (e.)