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A coil of inductance 0.50 H and resistance 100Omega is connected to a 240 V, 50 Hz ac supply. (a) What is the maximum current in the coil? (b) What is the time lag between the voltage maximum and the current maximum? |
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Answer» Solution :For an LR circuit, if `V=V_(0)sin OMEGA t` `I=(V_(0))/(sqrt(R^(2)+omega^(2)L^(2))) sin (omega t -phi)`, where `tan phi=(omega L//R)`. (a) `I_(0)=1.82A` (b) V is MAXIMUM at t = 0, I is maximum at `t=(phi//omega)`. Now, `tan phi=(2PI VL)/(R ) = 1.571 or phi ~~57.5^(@)` Therefore, TIME lag `=(57.5pi)/(180)xx(1)/(2pi xx 50)=3.2 ms` |
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