Answer:
sorry I don't understand this language
The correct answer is
b. low frequencies and low energy.
In fact, microwaves and radio waves have frequency up to
, which are really low compared, for instance, to the frequency of gamma rays (
). Moreover, the energy of an electromagnetic wave is directly proportional to its frequency:

where h is the Planck constant and f the frequency; therefore, low frequency means also low energy.
Answer:
There are 5 valence electrons
Explanation:
Valence electrons are electrons found in the outermost shell of an atom.
Newtons 3.law: Action = Reaction
If a body exerts a force on a rope of 400 N the rope exerts a force on the body of 400N also. So the tension in the rope is 400N. See pictures below.
Answer:
<h2>
500m</h2>
Explanation:
Using the equation of motion S = ut + 1/2 gt²
S = the vertical displacement (in m)
u = initial velocity of the object (in m/s)
g = acceleration due to gravity (in m/s²)
t = time taken (in secs)
Given u = 0m/s, g = 10m/s² and t = 10s, substituting this value into the equation to get the vertical displacement w have;
S = 0+1/2 (10)(10)²
S = 1000/2
S = 500m
The vertical displacement after 10seconds is 500m