Question

In the circuit diagram, all the bulbs are identical. Which bulb will be the brightest?

• A. $A$
• B. $B$
• C. $D$
• D. $C$

Answer 1

The correct option is D $C$

Now, Brightness $\propto$ Power of the bulb $\propto \left({\text{current}}^2\right)$
As bulb $C$ has the same current $\left(i\right)$ as that through the battery, while the
branches with bulbs $A,B$ and $D$ are in parallel and have only some fraction of total current from the
battery passing through them, the current through bulb $C$ is greatest and hence it will be the brightest.
Therefore, option $\left(c\right)$ is correct.