Two heater wires of equal length are first connected in series and then in parallel. The ratio of heat produced in the two cases is

An electric kettle has two heating coils. When one coil is used, water in the kettle boils in $5$ minutes, while when second coil is used, same water boils in $10\,\min$. If the two coils, connected in parallel are used simultaneously, the same water will boil in time

Two resistances ${R_1}$ and ${R_2}$ when connected in series and parallel with $120\, V$ line, power consumed will be $25\, W$ and $100\, W$ respectively. Then the ratio of power consumed by ${R_1}$ to that consumed by ${R_2}$ will be

The resistance of a heater coil is $110\, ohm$. A resistance $R$ is connected in parallel with it and the combination is joined in series with a resistance of $11\, ohm$ to a $220\, volt$ main line. The heater operates with a power of $110\, watt$. The value of $R$ in $ohm$ is

A coil takes $15\,\min$ to boil a certain amount of water, another coil takes $20\,\min$ for the same process. Time taken to boil the same amount of water when both coil are connected in series ........... $min$

If a power of $100\, W$ is being supplied across a potential difference of $200\, V$, current flowing is ............ $A$