Is the same true for rms voltage? (b) A capacitor is used in the primary circuit of an induction coil. (c) An applied voltage signal consists of a superposition of a dc voltage and an ac voltage of high frequency. The circuit consists of an inductor and a capacitor in series.
Show that the dc signal will appear across C and the ac signal across L . (d) A choke coil in series with a lamp is connected to a dc line. The lamp is seen to shine brightly. Insertion of an iron core in the choke causes no change in the lamp’s brightness.
Predict the corresponding observations if the connection is to an ac line. (e) Why is choke coil needed in the use of fluorescent tubes with ac mains? Why can we not use an ordinary resistor instead of the choke coil? .
A power transmission line feeds input power at V to a step- down transformer with its primary windings having turns. What should be the number of turns in the secondary in order to get output power at V? . At a hydroelectric power plant, the water pressure head is at a height of m and the water flow available is m s – .
If the turbine generator efficiency is %, estimate the electric power available from the plant ( g = . ms – ). . A small town with a demand of kW of electric power at V is situated km away from an electric plant generating power at V.
The resistance of the two wire line carrying power is . Ω per km. The town gets power from the line through a - V step-down transformer at a sub-station in the town. (a) Estimate the line power loss in the form of heat.
(b) How much power must the plant supply, assuming there is negligible power loss due to leakage? (c) Characterise the step up transformer at the plant. . Do the same exercise as above with the replacement of the earlier