Question

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

Answer 1

Hint : As a first step, analyse the circuit and hence find the parallel and series connections in it. Now, recall that the maximum current would imply maximum magnitude of power which further ensures greater intensity. So, find the bulb through which there would be maximum current flow and that would shine the brightest.

Complete step-by-step solution:
In the circuit we are given a circuit with four bulbs connected to the battery as shown in the figure. We are supposed to find the bulb among them that shines the brightest.
So, the bulb that shines the brightest means the intensity is the highest and so the power should also be of the highest value in that bulb. Now for the power to have highest value, we know that the current flow should be highest in that particular bulb from the following relation,
$P={{I}^{2}}R$
Where, P is power and I is the current.
Now, let us analyse the given circuit to find the bulb in which the highest current flow is present.
For series connection the current would be the same and for parallel connection the current is split between those branches.
So, the maximum current for the given potential will flow through the bulb C and after passing through C the current is divided between the branches shown.
Higher current would imply higher power from the above relation and so the bulb C would shine the brightest among them.

Note: We have given the basic understanding of the current flow in a circuit. Now for the voltage, we have the same value for parallel branches as it is measured between two points and for series connection it would be different. Also, from Kirchoff’s Current rule, we have the sum of the current entering and leaving the junction to be equal.