Solve the Problem $E$ Is Modeled By $E = 2.7 \cos 38 \pi t$

Multiple Choice

Solve the problem.
-For an electrical circuit, the voltage $E$ is modeled by $E = 2.7 \cos 38 \pi t$ , where $t$ is the time in seconds. How many cycles are completed in one second?

A) 38 cycles
B) $38 \pi$ cycles
C) 19 cycles
D) $2.7$ cycles