(a) Sketch the magnetic flux pattern around a long; straight, current-carrying wire (b) State two methods by which the sensitivity of a moving-coil galvanometer can be increased. (c) A series RLC circuit comprises a 100- resistor, a 3-H inductor and a 4-f capacitor. The a.c source of tile circuit has an e.m.f of 100V and a frequency of 160 Hz. (i) Draw the circuit diagram of the arrangement. Calculate the: (ii) capacitive reactance; (iii) inductive reactance: (iv) impedance of the circuit; (v) current in the circuit; (vi) average power dissipated in the circuit.
Explanation
(a)
(b) The sensitivity is increased by a weak spring and increasing the strength of the magnet C (c)(i)
(ii) X = = 781 (iii) X = 2fL = 2 x x 3 = 960 (iv) Z = = 205 (v) I = (vi) P = I = (0.49) x 100 = 23.795 W = 24W
