AC Frequency: Calculating from V, I, & t

[arod2812]

Homework Statement

A light bulb is connected to a 120.0-V wall socket. The current in the bulb depends on the time t according to the relation I = (0.669 A) sin [(491 Hz)t].

What is the frequency of the alternating current?

Homework Equations

How do I use the given value for I?? (since it includes time, t)

The Attempt at a Solution

I know that V=Vo * sin2pi * freq * time

 

[mezarashi]

The only relevant equation you should be using is:

sin(kt)

Suppose I have the equation sin(pi*x), can you tell me what the period of this function is? Can you tell me the frequency? Draw it out. Now if I tell you I have the equation sin(491*x), can you tell me the same information?

You will notice a pattern such as: sin(k*x) -> sin(2*pi*f*x) in terms of frequency.