Question

What is the period and amplitude for `I(t) =120 sin (10pix - pi/4)`?

Answer 1

A general time-dependent wave function can be represented in the following form:

`y = A*sin(kx-omegat)`

where,
`A` is amplitude
`omega = (2pi)/T` where `T` is time period
`k = (2pi)/lamda` where `lamda` is the wavelength

So, comparing with the given equation `I(t) =120 sin (10pix - pi/4)`, we can find:

Amplitude (`A`) = 120

Now, your supplied equation has no t- dependent parameter in the sine function, whereas the L.H.S. clearly indicates it is a time-dependent function [`I(t)`]. So, this is impossible!

Probably, your equation was supposed to be `I(t) =120 sin (10pix - pi/4t)`

Under that condition,
`omega = pi/4`
`=> pi/4 = (2pi)/T`
`=> T = 8` units