1. Frequency: 
The frequency of a light wave is given by:

where
is the speed of light
is the wavelength of the wave
In this problem, we have light with wavelength

Substituting into the equation, we find the frequency:

2. Period: 
The period of a wave is equal to the reciprocal of the frequency:

The frequency of this light wave is
(found in the previous exercise), so the period is:

Answer:
The distance from charge 5 μ C = 26.45 cm and the distance from - 4 μ C is 23.55 cm.
Explanation:
Given that
q₁ = 5 μ C
q₂ = - 4 μ C
The distance between charges = 50 cm
d= 50 cm
Lets take at distance x from the charge μ C ,the electrical field is zero.
That is why the distance from the charge - 4 μ C = 50 - x cm
We know that ,electric field is given as


Therefore the distance from charge 5 μ C = 26.45 cm and the distance from - 4 μ C is 23.55 cm.
Given the distance traveled and time elapsed, the average speed of the train is approximately 26.944m/s.
<h3>What is the average speed of the train?</h3>
Speed is simply referred to as distance traveled per unit time.
Mathematically, Speed = Distance ÷ time.
Given the data in the question;
- Distance traveled = 221miles
- Elapsed time = 3 hours and 40 minutes
First we convert miles to meters and Hours minutes to seconds.
221 miles = ( 221 × 1609.344 )m = 355665.024 meters
3 hours and 40 minutes = ( 3×60×60)s + ( 40×60)s
= 10800s + 2400s
= 13200s
Now, determine the average speed.
Speed = Distance ÷ time
Speed = 355665.024m / 13200s
Speed = 26.944m/s
Given the distance traveled and time elapsed, the average speed of the train is approximately 26.944m/s.
Learn more about speed here: brainly.com/question/7359669
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