The instantaneous voltage through a device of impendance 20 `Omega` is V=`80sin100pit`. The effective value of the current is

Options

A. 0.125
B. 2.828 A
C. 1.732 A
D. 0.16666666666667

Answer

B

Explanation

The instantaneous voltgae through the given device,
`V=80sin100pit`
Comparing the given instantaneous voltage with standard instantaneous voltage
`V=V_(0)sin omegat, ` we get `V_(0)=80V`
Where, `e_(0)` is the peak value of voltage
`V=V_(0)sinomegat,` we get `V_(0)=80V`
where, `e_(0)` is the peak value of voltage. ltBrgt Impedance, `Z=20Omega`
Peak value of current, `l_(0)=(V_(0))/(Z)=(80)/(20)=4A`
Effective value of current (root mean square value of current)
`l_(rms)=(l_(0))/(sqrt(2))=(4)/(sqrt(2))=2sqrt(2)=2.828A`