Question

If V=100sin (100t)V and I =100sin `(100t+(pi)/(3))` mA are the instantaneous values of voltage and current, respectively
A. `70.7 V, 70.7 mA`
B. `70.7 V, 70.7 A`
C. `141.4 V,141.4 mA`
D. `100 V,100 mA`

Answer 1

Correct Answer - A
The instantaneous value of voltage is
V = 100 sin (100t) V
Compare it with, `V=V_(0) sin(omega t)V`
we get, `V_(0)=100 V, omega = 100 "rad " s^(-1)`
The rms value of voltage is
`V_("rms")=(V_(0))/(sqrt(2))=(100)/(sqrt(2))V=70.7 V`
The instantaneous value of current is
`I = 100 sim (100 t +(pi)/(3))mA`
Compare it with, `I = I_(0)sin (omega t+phi)`
we get, `I_(0) = 100 mA, omega = 100 "rad " s^(-1)`
The rms value of current is
`I_("rms")=(I_(0))/(sqrt(2))=(100)/(sqrt(2))mA=70.7 mA`