the awnser is a and i hope that helps
I will assume here that the well is sufficiently short so that the time the sound takes to come from the bottom of the well to our ear is negligible.
Since the pebble moves by uniformly accelerated motion, the distance it covers is given by

where

is the gravitational acceleration

is the time the pebble takes to reach the bottom of the well
Therefore, the depth of the well is

and the correct answer is B.
Answer:add resistance in the parallel circuit with the total resistance
Explanation:
the total resistance in the parallel circuit is also add resistance.
The answer is reverse faults.
The characteristics of high energy wave length are:
- High Frequencies
- Short wave length
And in term of color, it will be located on the red spectrum.