In an ideal transformer, number of turns in the primary and secondary are 200 and 1000 respectively. If the power input to the primary is 10 kW at 200 V, Calculate 

(b) current in the primary ?

A small town with a demand of 800 kW of electric power of 220 V is situated 15 km away from an electric plant generating power at 440 V. the resistance of the two wire line carrying power is $0.5 \Omega per km.$ The town gets power from the line through a 4000-220 V step-down trunsformer at a sub-station in the town 

(a) Estimate the line power less in the form of heat.

A small town with a demand of 800 kW of electric power of 220 V is situated 15 km away from an electric plant generating power at 440 V. the resistance of the two wire line carrying power is 0.5 Ω per km.0.5 Ω per km. The town gets power from the line through a 4000-220 V step-down transformer at a sub-station in the town. How much power must the plant supply, assuming there is negligible power less due to leakage ?

A small town with a demand of 800 kW of electric power of 220 V is situated 15 km away from an electric plant generating power at 440 V. the resistance of the two wire line carrying power is 0.5 Ω per km.0.5 Ω per km. The town gets power from the line through a 4000-220 V step-down transformer at a sub-station in the town. Characterise the step-up transformer at the plant.

Let $\mathrm{c}$ be the capacitance of a capacitor discharging through a resistor $\mathrm{R}$. Suppose ${\mathrm{t}}_1$ is the time taken for the energy stored in the capacitor to reduce to half of its initial value and ${\mathrm{t}}_2$ the time for the charge to reduce to one fourth of its initial value. Then ratio of $\frac{\mathrm{t}}{{\mathrm{t}}_2}$ will be

A parallel plate capacitor $\mathrm{C}$ with plates of unit area and separation $\mathrm{d}$ is filled with a liquid of dielectric constant $\mathrm{k}=2$ The level of liquid is $\frac{\mathrm{d}}{3}$ initially. Fig. Suppose the liquid level decreases at a constant speed $\mathrm{v}$, the time constant as a function of time is