Chapter 18, Problem 5Q

To determine

To explain:

The meaning of the expression - One terminal of a car battery is said to be connected to “ground”, since it is not really connected to the ground

Answer to Problem 5Q

Solution:

In cars we do not have the ‘earth-ground’ but the ‘chassis-ground’.

Explanation of Solution

It is correct that the car-battery is not really connected to the ground, other-wise how will the car move, but in case of cars what we do is that the negative terminal of the battery is connected to the chassis of the body after cleaning all the rust, dust, paint etc. from the contact point, i.e. directly to the metal of the chassis.

The other circuitry of the car like stereo, electronic engine control, special-lights and fuel-pump are also connected with the chassis of the car. Thus, the chassis actually works like a reference potential maintainer for all the equipments of the car which are connected with the positive terminal of the battery and the other terminal of all those equipments, are connected with the chassis to complete the circuitry. So, we do not need to run two wires from the battery to an electrical equipment of the car.