Question

The vehicles carrying inflammable fluids usually have metallic chains touching the ground :

• A. To conduct excess charge due to air friction to ground and prevent sparking.
• B. To alert other vehicles.
• C. To protect tyres from catching dirt from ground.
• D. It is a custom.

Answer 1

The Correct Option is A

When vehicles move, particularly at high speeds, friction between the vehicle body and the air can cause the accumulation of static electric charge on the surface of the vehicle. For vehicles carrying inflammable fluids, the presence of static electricity poses a significant risk as it can lead to sparking, which may cause combustion or an explosion if the fluid is highly flammable.
To mitigate this risk, metallic chains are often attached to such vehicles, ensuring that they touch the ground. The metallic chains provide a conductive path for the excess static charge to flow safely to the ground, thereby preventing the buildup of static electricity and reducing the risk of sparking.

Answer 2

Step 1: Understanding the situation.
When vehicles move at high speed, air friction causes them to accumulate electric charges on their metallic surfaces, especially when carrying inflammable fluids like petrol or diesel. This buildup of static electricity can be dangerous if not discharged properly.

Step 2: Role of the metallic chain.
The metallic chain that touches the ground provides a continuous conductive path between the vehicle and the earth. Any excess electric charge generated due to air friction flows safely to the ground through this chain.

Step 3: Purpose of grounding.
By conducting the charge to the ground, the chain prevents the accumulation of static electricity, thereby avoiding possible sparking or ignition of inflammable vapors around the vehicle.

Final Answer: To conduct excess charge due to air friction to ground and prevent sparking.