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Q2) A d.c. relay coil has an inductance of 400 mH and a time-constant of 1.6 ms. The current rises to 86.5 mA after 3.2 ms from switch on.

Calculate EACH of the following:

(a) the coil resistance; (2)

(b) the maximum current; (3)

(c) the supply voltage; (2)

(d) the current 4 ms after switch-on; (3)

(e) the time taken for the current to reach 70 mA; (4)

(f) the final value of the stored energy. (2)