Answer:
a)  v = 2,9992 10⁸ m / s
, b)  Eo = 375 V / m
,  B = 1.25 10⁻⁶ T,
 c)     λ = 3,157 10⁻⁷ m,   f = 9.50 10¹⁴ Hz
,  T = 1.05 10⁻¹⁵ s
, UV
Explanation:
In this problem they give us the equation of the traveling wave
         E = 375 cos [1.99 10⁷ x + 5.97 10¹⁵ t]
a) what the wave velocity
all waves must meet
         v = λ f
In this case, because of an electromagnetic wave, the speed must be the speed of light.
         k = 2π / λ
         λ = 2π / k
         λ = 2π / 1.99 10⁷
         λ = 3,157 10⁻⁷ m
         w = 2π f
         f = w / 2 π
         f = 5.97 10¹⁵ / 2π
         f = 9.50 10¹⁴ Hz
the wave speed is
         v = 3,157 10⁻⁷   9.50 10¹⁴
         v = 2,9992 10⁸ m / s
b) The electric field is
            Eo = 375 V / m
to find the magnetic field we use
            E / B = c
            B = E / c
             B = 375 / 2,9992 10⁸
             B = 1.25 10⁻⁶ T
c) The period is
            T = 1 / f
             T = 1 / 9.50 10¹⁴
             T = 1.05 10⁻¹⁵ s
the wavelength value is
           λ = 3,157 10-7 m (109 nm / 1m) = 315.7 nm
this wavelength corresponds to the ultraviolet
 
        
             
        
        
        
Limited resources: resources that take a long time to replenish
Example: coal, oil, nuclear gas
Non- limited resource: resources that are constantly being replenished
Example: soil, wind, water
        
             
        
        
        
Answer:
20m in 2 secs
Explanation:
t=2s
s=20m
hence the maximum height reached by stone is 20m in 2 s
 
        
             
        
        
        
Wave speed = (wavelength) x (frequency)
We know the wavelength, but we don't know the frequency. How can we find the frequency ?  "Here frequency frequency."
We know the period, and frequency is just (1 / period).  So . . . 
Wave speed = (wavelength) / (period)
Wave speed = (2.1 meters) / (9.4 seconds)
Wave speed = (2.1 / 9.4) m/s
<em>Wave speed = 0.223 m/s</em>