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Q10. A relay coil has resistance of 200Ω and the current required to operate the relay is 150 mA. When the relay is connected to a 50 V d.c. supply the time between switch on and the operation of the relay is 40 ms.

(a) Calculate EACH of the following:

(i) The steady state relay current;

(ii) The time constant for the coil;

(iii) The inductance of the coil.

(b) To increase the operating time delay for the relay a 50 resistor is connected in series with the coil. Calculate the new time delay for the relay.