If so, the field strength would be largest when thunderstorm activity is greatest.
A
lightning stroke heats the air along its path to as much as 1 0,000°
C (18,000° F).
Tremendous
expansion of the air column follows, sending a vibrating pressure
wave outward.
This
wave, moving at almost 3000 m/s (1000 ft/s), i. e., at the speed of
sound, makes the noise known as thunder.
We
can compute how far away the lightning is by counting the number of
seconds between the time when the lightning flash is seen and the
time when the thunder is heard, at least up to 10 s, which indicates
a distance of 3 km (2 miles).
At
greater distances the sound may become refracted, so that cult to
associate thunderclaps with the correct strokes.
Задание
2. Найти в тексте предложения, являющиеся
ответами на вопросы:
1.
When does the peak of the electric field strength occur?
2.
What is thunder?
3.
How can we compute how far the lightning is?
