The figure shows a network of four resistances and three batteries. The electrical power dissipated as heat in the circuit is .............. $W$.

Two bulbs consume the same power when operated at $200\, V$ and $300\, V$ respectively. When these bulbs are connected in series across a $D.C.$ source of $500\, V$,then:

$A$ room has an $AC$ running for $5$ hours a day at a voltage of $220$ $V$. The wiring of the room consists of $Cu$ wire of $1$ $mm$ radius and a length of $10$ $m$. Power consumption per day is $10$ commercial units. What fraction of it goes into Joule heating in the wires? What would happen if the wiring is made of aluminium of the same dimensions? $(\rho_{Cu} = 1.7 \times 10^{-8} \, \Omega m, \rho_{Al} = 2.7 \times 10^{-8} \, \Omega m)$

$A$ power of $100 \ W$ is used at $125 \ V$ to produce chlorine by electrolysis. How many $mg$ of chlorine are produced per minute? (The electrochemical equivalent of chlorine is $0.367 \times 10^{-6} \ kg/C$)

The terminal voltage $V$ across a battery of $emf$ $E$ and internal resistance $r$ can be:

Which of the following graphs represents the variation of power loss in the external load with external resistance $R$?