Multiple Choice
An AC emf source is given by. What is the instantaneous emf of this source at ?
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31. Alternating Current
Alternating Voltages and Currents
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Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
An AC source produces an alternating current in a circuit with the function i(t)=(1.5A)cos[(250s−1)t]. What is the frequency of the source? What is the maximum current in the circuit?
A
f=39.3 Hz
B
f=250 Hz
C
f=393 Hz
D
f=1570 Hz
Verified step by step guidance1
Identify the given function for the alternating current: i(t) = (1.5 A) cos[(250 s^{-1}) t].
Recognize that the function is in the form i(t) = I_0 cos(ωt), where I_0 is the maximum current and ω is the angular frequency.
Determine the maximum current, I_0, from the function. Here, I_0 = 1.5 A.
Identify the angular frequency, ω, from the function. Here, ω = 250 s^{-1}.
Use the relationship between angular frequency and frequency: ω = 2πf, to solve for the frequency, f. Rearrange to find f = ω / (2π).
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