Find the potential of point $J$ with respect to point $G$. (in $V$)

An electric heater and an electric bulb are rated $500\, W, 220\, V$ and $100\, W, 220\, V$ respectively. Both are connected in series to a $220\, V$ $a.c.$ mains. The power consumed by the heater and the bulb respectively is:

Five identical resistors, each of resistance $R = 1500 \Omega$, are connected to a $300 \text{ V}$ battery as shown in the circuit. The reading of the ideal ammeter $A$ is: (in $\text{ A}$)

In the figure shown,the total resistance between $A$ and $B$ is ............. $\Omega$.

The maximum power dissipated in an external resistance $R$,when connected to a cell of emf $\varepsilon$ and internal resistance $r$,will be . . . . . . .

Model a torch battery of length $l$ to be made up of a thin cylindrical bar of radius $a$ and a concentric thin cylindrical shell of radius $b$,filled in between with an electrolyte of resistivity $\rho$ (see figure). If the battery is connected to a resistance of value $R$,the maximum Joule heating in $R$ will take place for: