Final answer:
The period of the sinusoidal voltage wave, given by the equation V(t) = 300 cos(120πt + 30°), can be calculated to be approximately 16.67 milliseconds.
Step-by-step explanation:
The period of the voltage wave is determined by the frequency of the sinusoidal function. Since we have the expression for voltage as V(t) = 300 cos(120πt + 30°), we can identify that the angular frequency ω is 120π rad/s. To find the frequency 'f', we use the relationship ω = 2πf, which gives us f = 60 Hz. Hence, the period 'T' is the reciprocal of the frequency, T = 1/f. For a frequency of 60 Hz, the period is T = 1/60 seconds or approximately 16.67 ms (milliseconds).