Two electric bulbs have resistances in the ratio $1 : 2$. If they are connected in parallel to a constant voltage source,the ratio of power dissipated in them will be:

In a $Ag$ voltameter,$2.68 \, g$ of silver is deposited in $10 \, \min$. The heat developed in a $20 \, \Omega$ resistor during the same period will be:

$n$ identical bulbs,each designed to draw a power $P$ from a certain voltage supply,are joined in series across that supply. The total power which they will draw is

Water boils in an electric kettle in $20$ minutes after being switched on. Using the same main supply,the length of the heating element should be . . . . . . to . . . . . . times of its initial length if the water is to be boiled in $15$ minutes.

How many units are consumed if a $100\,W$ electric bulb is kept $ON$ for $10$ hours?

$A\, 5\, ^oC$ rise in the temperature is observed in a conductor by passing some current. When the current is doubled,then the rise in temperature will be equal to ............. $^oC$.