Using the flash to bang method, what is the multiplier for converting seconds to meters for distance estimation?

In the context of estimating the distance to a flash (such as an explosion or artillery fire) using the flash to bang method, the multiplier used to convert the time gap between seeing the flash and hearing the bang into distance in meters is based on the speed of sound. The speed of sound in air is approximately 343 meters per second at sea level and at standard temperature.

When using this method, each second of time elapsed between seeing the flash and hearing the bang can be multiplied by a factor to estimate the distance. The commonly accepted multiplier is 350 meters per second. This allows for a quick estimation of distance; if you see a flash and count the seconds until you hear the associated sound, multiplying the number of seconds counted by 350 gives you a close approximation of how far away the source of the flash is.

Thus, the correct choice is the first option of 350, aligning with standard practice in fire support and distance estimation techniques.