Two heating coils of resistances $10 \Omega$ and $20 \Omega$ are connected in parallel and connected to a battery of emf $12 \text{ V}$ and internal resistance $1 \Omega$. The ratio of the power consumed by them is:

$A$ constant voltage is applied between two ends of a metallic wire. If the length is halved and the radius of the wire is doubled,the rate of heat developed in the wire will be

If voltage across a bulb rated $220 \text{ V} - 100 \text{ W}$ drops by $2.5\%$ of its rated value,the percentage of the rated value by which the power would decrease is ............... $\%$

The current density in a circular wire is given by $J(r) = (1 \times 10^5 \text{ A/m}^3) r$,where $r$ is the radial distance and the wire's radius is $2 \text{ mm}$. If the potential applied across the wire is $70 \text{ V}$,then the energy consumed by the wire in $1000 \text{ s}$ is:

Two electric bulbs have power ratings $P_1$ and $P_2$ at voltage $V$. They are connected in parallel to a voltage source $V$. What is the total power consumed?

What is the value of $1 \, kWh$ in Joules?