A coil of inductance 4 H and resistance 80 Ω is in parallel with a 200 Ω resistor of negligible inductance across a 200 V d.c.supply. The switch connecting these to the supply is then opened, the coil and resistor remaining connected together. State, ineach case, for an instant immediately before and for one immediately after the opening of the switch: (a) the current throughthe resistor; (b) the current through the coil; (c) the e.m.f. induced in the coil; and (d) the voltage across the coil. Give roughsketch graphs, with explanatory notes, to show how these four quantities vary with time. Include intervals both before andafter the opening of the switch, and mark on the graphs an approximate time scale.

Kamarenga , 5 Years ago

Grade 12th pass