Final answer:
The student's question involves analyzing a sinusoidal wave to determine its periodicity and fundamental period, as well as finding amplitude, frequency, and period of an electromagnetic wave. More context is needed to fully resolve the first part, but the electromagnetic wave has an amplitude of 30 V/m, a frequency of 4.0 MHz, and a period of 0.25 μs.
Step-by-step explanation:
The student is asking about the characteristics of sinusoidal waves, focusing on periodicity, fundamental periods, amplitude, frequency, and the period of the waves.
For the function sin [30/105πn+4], to determine if the signal is periodic and its fundamental period, one must look at the argument of the sine function. However, more context is needed to accurately provide this information.
Concerning the electromagnetic wave with an electric field described by E = (30) sin (4.0×106t), the amplitude is 30 V/m, the frequency is 4.0 MHz (since the angular frequency ω = 2πf, and ω is given as 4.0×106 rad/s), and the period (T) is the inverse of the frequency, which is 0.25 × 10-6 s or 0.25 μs. A graph of this electric field would show a sinusoidal wave with these properties.