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Q2) When connected to a 20 V d.c supply a relay starts to operate 0.52 ms after swiching on the supply at which time the instantaneous current is 200m mA. The relay coil has a time constant of 5 ms.

(a) Calculate EACH of the following:

(i) the final steady state relay current; (5)

(ii) the resistance of the relay coil; (2)

(iii) the inductance of the relay coil. (2)

(b) To increase the operating time a 40 Ω resistor is connected in series with the relay coil.  Calculate the new operating time for the relay assuming the instantaneous current is 200 mA.