Question

A 100 W bulb $B_1$, and two 60 W bulbs $B_2$ and $B_3$, are connected to a 250 V source as shown in the figure. Now $W_1,W_2$ and $W_3$ are the output powers of the bulbs $B_1,B_2$ and $B_3$ respectively. Then

• A. $W_1>W_2=W_3$
  
• B. $W_1>W_2>W_3$
• C. $W_1<W_2=W_3$
• D. $W_1<W_2<W_3$

Answer 1

The correct option is D

$W_1<W_2<W_3$

Let the resistance of 100 W bulb is $R_1$ and that of 60 W bulb is $R_2$. From the given data we can conclude that $R_1<R_2$.

Now if we observe the current in the branches, we can say that the current in $B_3$ is more than that of $B_1$ and $B_2$.

Both these observations says that the power output can be arranged as :

$W_1<W_2<W_3$