Chapter 19, Problem 6Q

To determine

Arrangement of two identical light bulbs and two identical batteries to obtain maximum power from the light bulbs?

Answer to Problem 6Q

Solution:

The maximum power from the light bulbs will be obtained when the batteries are attached in series connection and bulb are connected in the parallel connection.

Explanation of Solution

Given:

Two identical batteries

Two identical bulbs of same resistance

Formula used:

The power of the light bulb is given as

        $P=\frac{V^2}{R}$

Here,

        $P$ is the power

        $V$ is the voltage

        $R$ is the resistance of the bulb

It is clear from the above formula that to obtain the maximum power from the bulb, the voltage should be maximum, while the resistance of the bulb should be minimum.

Since, we know that, in series connection, total voltage of the batteries is the sum of voltage of individual battery, and the maximum voltage can only be obtained when batteries are connected in series connection.

While the resistance of the bulbs will be minimum when the bulbs are connected in parallel connection, as in parallel connection the total resistance of the bulbs is minimized.