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Electricity and Magnetism

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Values of Alternating Current at Different TImes

EANDM-NOLBP0

The current in a circuit is a function of time and is given by: $I=I_{peak}cos(2\pi f t)$.

If the value of the current at $t=0\, sec$ is $5\,A$, and first reaches the value of $0\,A$ at $t=10\,sec$, what is the value of the frequency, $f$, and what is the value of the rms current $I_{rms}$?

A

$f=10\,Hz$
$I_{rms}=3.54\,A$

B

$f=0.025\,Hz$
$I_{rms}=7.07\,A$

C

$f=0.025\,Hz$
$I_{rms}=3.54\,A$

D

$f=0.10\,Hz$
$I_{rms}=3.54\,A$

E

$f=0.05\,Hz$
$I_{rms}=7.07\,A$