Answer: (A) The number of waves that pass a point in a certain amount of time.
Explanation:
Electromagnetic waves are categorized according to their frequency f or, equivalently, according to their wavelength λ = c/f. Visible light has a wavelength range from ~400 nm to ~700 nm.
Frequency: Is the number of waves that pass a certain point in a specified amount of time.
Trough: The low point of the wave cycle.
Wavelength: The distance between two successive peaks.
Electromagnetic wave: One of the waves that are propagated by simultaneous periodic variations of electric and magnetic field intensity.
Answer:
the tension in each side of the cable is 3677.57 N
Explanation:
given data
traffic light = 20 kg
cable between two poles = 30 m
sag in the cable = 0.40 m
solution
by the free body diagram
tan θ =
.............1
θ = 1.527 °
and
tension = mg
The net force is along x - axis is express as
T2 cosθ = T1 cosθ .................2
so T2 - T1 ..............3
and
when we take it along y axis that is express as
( T1 + T2) sinθ = mg ...................4
so by equation 3 we put here
2 × T1 sin(1.527) = 20 × 9.8
T1 = 3677.57 N