Question

A general rule for estimating the distance in kilometers between an observer and a lightning bolt is to count the number of seconds between seeing the lightning and hearing it, and dividing by
a) 5
b) 3
c) 2
d) 4
e) none of these

Answer 1

Answer:

option b ) is correct

Explanation:

Let d be the distance in km from the place of lightning . velocity of sound is 340 m /s approx

in km/ s it is 0.34 km/s

time in sec  taken by sound to cover a distance of d km

d / .34 = t

d = .34 t

d = $\frac{t}{\frac{1}{0.34} }$

d = t / 3

so option b ) is correct .  ,