Question

Q.11 A circuit consist of two
resistances 100 and 200 in parallel
when connected across 240 V
supply ,then the value of current is
Ans:
O 254
O 16A
O 36A
O 40A​

Answer 1

Answer:

Normally it is a common feeling that we are adding two bulbs in series and so their consumption should add up. But, when we make a series connection, both the bulbs do not get 250V because of voltage drop for series connection.

Power varies in square of the available voltage across the terminals of the bulb. In practical life also when you add the bulbs in series you see the glow is diminished as voltage available at the terminals are much less than the supply voltage.

For the given problem calculate the resistance of the bulbs by R=V^2/W. Get the series current by I= 250/(R1+R2) and then calculate total power by W=I^2*(R1+R2).