177. A three-by-three, series-parallel matrix of resistors, all having the same ohmic value, would have a net resistance of

The following three impedances are connected in series across a 40 V, 20 kHz supply: a 
resistance of 8 Ω, a coil of inductance 130 μH and 5 Ω resistance, and a 10 Ω resistor in 
series with a 0.25 µF capacitor. Sketch a neat diagram representing this network, and 
calculate:
5.1.1 The inductive and capacitive reactance’s. (4)
5.1.2 The magnitude and phase angle of the circuit impedance. (4)
5.1.3 The voltage drops across resistance, inductance and capacitance.

A coil having an inductance of 6 H and an unknown resistance is connected in series with 
a resistor of 10 Ω to a 120 V dc supply. The time constant of the circuit is 300 ms. When 
steady state conditions have been reached, the supply is replaced instantaneously by a short-circuit. Determine the resistance of the coil, the current flowing in the circuit one second after the shorting link has been placed in the circuit, and the time taken for the current to fall to 10% of its initial value. 

A coil having an inductance of 6 H and an unknown resistance is connected in series with 
a resistor of 10 Ω to a 120 V dc supply. The time constant of the circuit is 300 ms. When 
steady state conditions have been reached, the supply is replaced instantaneously by a shortcircuit. Determine the resistance of the coil, the current flowing in the circuit one second 
after the shorting link has been placed in the circuit, and the time taken for the current to 
fall to 10% of its initial value