Answer:
v = 2,99913 10⁸ m / s
Explanation:
The velocity of propagation of a wave is
v = λ f
in the case of an electromagnetic wave in a vacuum the speed that speed of light
v = c
When the wave reaches a material medium, it is transmitted through a resonant type process, whereby the molecules of the medium vibrate at the same frequency as the wave, as the speed of the wave decreases the only way that they remain the relationship is that the donut length changes in the material medium
λ = λ₀ / n
where n is the index of refraction of the material medium.
Therefore the expression is
v = 
Let's look for the frequency of blue light in a vacuum
f =
f = 
f = 6.667 10¹⁴ Hz
the refractive index of air is tabulated
n = 1,00029
let's calculate
v = 
450 10-9 / 1,00029 6,667 1014
v = 2,99913 10⁸ m / s
we can see that the decrease in speed is very small
Free insulative sheets and insulative sheets backed by a grounded conductor are the only cases in which it is possible to extract reliable information from a noncontacting measurement of the charged state of an insulator. In both cases, the electric field from the charge is the deciding factor.<span>
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The rate at which the height is changing is ( 5 / x ) m / hr
We know that,
Area of an equilateral triangle A = 
/ 4
h = x / 2
Where,
x = Side
h = Height
Given that,
dA / dt = 5 
/ hr
h = x / 2
Differentiate both sides with respect to t
dh / dt = ( / 2 ) ( dx / dt )
dx / dt = ( 2 / ) ( dh / dt )
A = / 4
Differentiate both sides with respect to t
dA / dt = ( / 4 ) ( 2x ) ( dx / dt )
5 = ( / 4 ) ( 2x ) ( 2 / ) ( dh / dt )
dh / dt = ( 5 / x ) m / hr
Rate of change of height is defined as the rate at which height of an object changes with respect to time. It is represented as dh / dt
Therefore, the rate at which the height is changing is ( 5 / x ) m / hr
To know more about Rate of change of height
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