The relevant formula we can use in this case would be:
h = v0 t + 0.5 g t^2
where,
h = height or distance travelled
v0 = initial velocity = 0 since it was dropped
t = time = 1 seconds
g = 9.8 m/s^2
So calculating for height h:
h = 0 + 0.5 * 9.8 m/s^2 * (1 s)^2
h = 4.9 meters
