Chapter 35, Problem 37A

If several bulbs are connected in series to a battery, they may feel warm to the touch even though they are not visibly glowing. What is your explanation?

To determine

The reason the bulb may be warm even though not glowing.

Explanation of Solution

Introduction:

In a series circuit, the equivalent resistance is more than each individual resistance. The flow of electron becomes difficult due to more resistance of the series circuit and current through the circuit decrease.

The bulbs are connected in a series connection with a battery. So, the equivalent resistance of bulbs is more than the resistance of each bulb. The flow of electrons through each bulb becomes difficult due to high equivalent resistance. The electrons have to do more work to move through the bulb. Some of the work done by the electron changes into heat due to the resistance of the bulb.

The electron has to do more work to pass through the bulb. So, the current through the bulb is reduced and the bulb is not visibly glowing. Some work of the electron converts into heat and the bulb may feel warm.

Conclusion:

The bulb is not visibly glowing in series connection due to less current and the bulb may feel warm due to the conversion of electrons work in the circuit into heat.