Two bulbs consume 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
Ratio of potential difference across them is $3/2$
Ratio of potential difference across them is $9/4$
Ratio of power consumed across them is $4/9$
Ratio of power consumed across them is $2/3$
A $220\, volt$, $1000\, W$ bulb is connected across a $110\, volt$ mains supply. The power consumed will be ............ $W$
In the circuit shown in figure, the heat produced in $5\, ohm $ resistance is $10\, cal / sec$ . The heat produced in $4$ resistance is ................ $cal /sec$
A rise of temperature of $4\,^oC$ is observed in a conductor by passing a current. If the current is tripled, the rise temperature will be .............. $^oC$
A $500\, W$ heating unit is designed to operate from a $115\, volt$ line. If the line voltage drops to $110\, volt$, the percentage drop in heat output will be ............... $\%$
$A$ wire of length $L$ and $3$ identical cells of negligible internal resistances are connected in series. Due to the current, the temperature of the wire is raised by $\Delta T$ in time $t. N$ number of similar cells is now connected in series with a wire of the same material and cross section but of length $2L$. The temperature of the wire is raised by the same amount $\Delta T$ in the same time $t$. The value of $N$ is :