Question

In the following figure all the bulbs connected are identical. The bulb that lights most brightly is :

• A. $only1$
• B. $only2$
• C. $4$ and $5$
• D. $2$ and $4$

Answer 1

The correct option is C $4$ and $5$

The bulb that has maximum power through it lights most brilliantly.The power through any bulb in the circuit is $i^{2}R$.

where, $i$ is the current passing through the given bulb, $R$ is the resistance of the bulb, same for all of them.

Since same current is present in both bulbs 4 and 5, and it further divides into bulbs 3, 1, and 2, the power and hence brightness is maximum for bulbs 4 and 5.