A resistance $R = 12\, \Omega$ is connected across a source of emf as shown in the figure . Its $emf$ changes with time as shown in the graph . What is the heat developed in the resistance in the first four seconds ? ............. $J$

Which device is used to transmit voltage over large distance ? why ?

An electric bulb rated as $200\, {W}$ at $100 \,{V}$ is used in a circuit having $200\, {V}$ supply. The resistance $'R'$ that must be put in series with the bulb so that the bulb delivers the same power is $.....\,\Omega$

Two electric bulbs, rated at $(25\, W, 220\, V)$ and $(100\, W, 220\, V)$, are connected in series acroos a $220\, V$ voltage source. If the $25\, W$ and $100\, W$ bulbs draw powers $P_1$ and $P_2$ respectively, then

Two resistors of $6\,\Omega $ and $9\,\Omega $ are connected in series to a $120\, volt$ source. The power consumed by the $6\,\Omega $ resistor is ........... $W$

The heat generated through $2 \,ohm$ and $8\, ohm$ resistances separately, when a condenser of $200\,\mu F$ capacity charged to $200\, V$ is discharged one by one, will be