A bulb is rated 40W,220V. Find the current drawn by it when it is connected to a 220V supply. Also find its resistance. (b) If the given bulb is replaced by a blub of rating 25W,220V will there be any change in the value of current and resistance? Justify your answer and determine the change.

A bulb is rated 40W,220V. Find the current drawn by it when it is conn

1.	A bulb is rated 40W,220V. Find the current drawn by it when it is connected to a 220V supply. Also find its resistance. (b) If the given bulb is replaced by a blub of rating 25W,220V will there be any change in the value of current and resistance? Justify your answer and determine the change.
Answer» Solution :(a) Here power of bulb P=40W and voltage V=220V `therefore` Current drawn by the bulb `I=P/V=40/220=2/11A` and resistance of the bulb `R=V/I=220/((2/11))=(220 TIMES 11)/2=1210 Omega` (b) On TAKING another bulb of power P.=25W and voltage V=220V there is a charge in the value of current and resistance because their VALUES depend on the power of the bulb. NEW current `I.-(P.)/V=25/220=5/44A` and new resistance `R.=V/(I.)=220/((5/44))=(220 times 44)/5=1936 Omega`