he power dissipated in the circuit shown in the figure is $30\,W$. The value of $R$  is ............. $\Omega$

Two conductors made of the same material are connected across a common potential difference. Conductor $A$ has twice the diameter and twice the length of conductor $B$. The power delivered to the two conductors ${P_A}$ and ${P_B}$ respectively is such that ${P_A}/{P_B}$ equals to

Two heaters $A$ and $B$ have power rating of $1 \mathrm{~kW}$ and $2 \mathrm{~kW}$, respectively. Those two are first connected in series and then in parallel to a fixed power source. The ratio of power outputs for these two cases is:

Two identical heaters rated $220\, volt$, $1000\, watt$ are placed in series with each other across $220 \,volt$ lines. If resistance do not change with temperature, then the combined power is ............. $watt$

$(1)$  The product of a volt and a coulomb is a joule.

$(2)$  The product of a volt and an ampere is a joule/second.

$(3)$  The product of volt and watt is horse power.

$(4)$  Watt-hour can be measured in terms of electron volt.

State if

The circuit below is used to heat water kept in a bucket. Assuming heat loss only by Newton's law of cooling, the variation in the temperature of the water in the bucket as a function of time is depicted by