Water of volume $2\, litre$ in a container is heated with a coil of $1\, kW$ at $27 \,^oC$. The lid of the container is open and energy dissipates at rate of $160\, J/s$. In how much time temperature will rise from $27\,^oC$ to $77\,^oC$ $[$ Given specific heat of water is $4.2\, kJ/kg$ $]$
$8 \,\min\,\, 20 \,s$
$6\,\min \,2 \,s$
$7\, \min$
$14 \,\min$
If a high power heater is connected to electric mains, then the bulbs in the house become dim, because there is a
A heating coil can heat the water of a vessel from $20\,^oC$ to $60\,^oC$ in $30$ minutes. Two such heating coils are put in series and then used to heat the same amount of water through the same temperature range. The time taken now will be ............ $min$ (neglecting thermal capacity of the coils)
The brightness of a bulb will be reduced, if a resistance is connected in
In the circuit shown below, the resistances are given (in $\Omega$ ) and the battery is assumed ideal with emf equal to $3.0 \,V$. The resistor that dissipates the most power is
This question has Statement $1$ and Statement $2.$ Of the four choices given after the Statements, choose the one that best describes the two Statements.
Statement $1 :$ The possibility of an electric bulb fusing is higher at the time of switching $ON.$
Statement $2:$ Resistance of an electric bulb when it is not lit up is much smaller than when it is lit up.