(a) (i) Write the principle of working of an ac generator. Draw its labelled diagram and explain its working. (ii) A resistor of 400 Ω, an inductor…

Write the principle of working of an ac generator. Draw its labelled diagram and explain its working.

A resistor of $\displaystyle 400 \Omega$, an inductor of $\displaystyle \left(\frac{5}{\pi}\right) \mathrm{H}$ and a capacitor of $\displaystyle \left(\frac{50}{\pi}\right) \mu \mathrm{F}$ are joined in series across an ac source $\displaystyle \mathrm{v}=140 \sin (100 \pi) \mathrm{tV}$. Find the rms voltages across these three circuit elements. The algebraic sum of these voltages is more than the rms voltage of source. Explain.

Write the principle of working of a transformer. With the help of a labelled diagram, explain the working of a step-up transformer.

An ideal transformer is designed to convert $\displaystyle 50$ V into $\displaystyle 250$ V. It draws $\displaystyle 200$ W power from an ac source whose instantaneous voltage is given by $\displaystyle \mathrm{v}_{\mathrm{i}}=20 \sin (100 \pi) \mathrm{tV}$. Find:

$$ rms value of input current.

expression for instantaneous output voltage.

expression for instantaneous output current.