In terms of the kinetic molecular theory what is the need four gaps
in railway lines
The gaps in railway lines are necessary to accommodate the expansion and contraction of the tracks due to changes in temperature. According to the kinetic molecular theory, as the temperature of a substance increases, the average kinetic energy of the particles in the substance also increases. This leads to the particles moving faster and spreading out, causing the substance to expand. Conversely, as the temperature decreases, the particles slow down and come closer together, causing the substance to contract.
In the case of railway lines, the metal tracks will expand in hot weather and contract in cold weather. Without gaps in the tracks, the expansion could cause the tracks to buckle or bend, leading to dangerous conditions for trains and passengers. Thus, the gaps in railway lines are essential to allow for the natural expansion and contraction of the tracks in response to temperature changes.