-- The speed of light in air is very close to 3 x 10⁸ m/s.
Whatever the actual number is, it's equivalent to roughly
7 times around the Earth in 1 second. So for this kind of
problem, you can assume that we see things at the same time
that they happen; don't bother worrying about how long it takes
for the light to reach you.
-- For sound, it's a different story. Sound in air only travels at
about 340 m/s. It takes sound almost 5 seconds to go 1 mile.
-- Now, the lightning and thunder happen at the same time.
The light travels to you at the speed of light, so you see the
lightning pretty much when it happens. But the sound of the
thunder comes poking along at 340 m/s, and arrives AFTER
the sight of the lightning.
The length of time between the sight and the sound is about
99.9999% the result of the time it takes the sound to reach you.
If the thunder arrived at you 3 seconds after the light did, then
the sound traveled
(340 m/s) x (3 s) = 1,020 meters .
(about 0.63 of a mile)
(If you're worried about ignoring the time it takes
for the light to reach you ...
It takes light 0.0000034 second to cover the same 1,020 meters,
so including it in the calculation would not change the answer.)
The significant figures also known as the significant digits or precision of a number written in positional notation are digits that carry meaningful contributions to its measurements
Base from the pressure-flow hypothesis, the sieve tube in the phloem should be living cells because sugars are transported across the membranes by the active transport which needs ATP that is produced during respiration. Hope this helps.
Adoption process of the SI system by all the worlds nations is called Metrication or metrification.
Metrication or metrification is defined as conversion to the metric system of units of measurement. Earlier, many traditional and local systems were used for conversion but since last 2 centuries, most of the countries have adopted the SI system that is widely used as system of measurement.
