A $60\, watt$ bulb operates on $220\,V$ supply. The current flowing through the bulb is
$11/3\, amp$
$3/11\, amp$
$3\, amp$
$6\, amp$
In the circuit shown, the resistance $r$ is a variable resistance. If for $r = fR,$ the heat generation in $r$ is maximum then the value of $f$ is
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 .............. $^oC$
What will happen when a $40\, watt$, $220\, volt$ lamp and $100\, watt$, $220\, volt$ lamp are connected in series across $40\, volt$ supply
Consider four circuits shown in the figure below. In which circuit power dissipated is greatest (Neglect the internal resistance of the power supply)
$A\,\,{5\,^o}C$ rise in the temperature is observed in a conductor by passing some current. When the current is doubled, then rise in temperature will be equal to ............. $^oC$