Ametallic conductor of irregular cross-section is as shown in the figure. Aconstant potential difference is applied across the ends $(1)$ and $(2)$. Then :
the current at the cross-section $P$ equals the current at the cross-section $Q$
the electric field intensity at $P$ is less than that at $Q.$
the rate of heat generated per unit time at $Q$ is greater than that at $P$
All of the above
An electric kettle takes $4\, A$ current at $220\, V$. How much time will it take to boil $1\, kg$ of water from room temperature $20\,^\circ C$ ? The temperature of boiling water is $100\,^\circ C$ .................. $minutes$
Ratio of thermal energy released in two resistor $R$ and $3 R$ connected in parallel in an electric circuit is :
A torch bulb rated as $4.5\, W, 1.5\, V$ is connected as shown in the figure. The $e.m.f.$ of the cell needed to make the bulb glow at full intensity is ............. $V$
Four equal resistance dissipated $5 \,W$ of power together when connected in series to a battery of negligible internal resistance. The total power dissipated in these resistance when connected in parallel across the same battery would be ........... $W$
On giving $220\,V$ to a resistor the power dissipated is $40\,W$ then value of resistance is ............... $\Omega$