Question

A resistance of $5 \Omega$ is connected in series with a capacitance of $1\,mF$ . The combination is connected to $AC$ source of angular frequency $200 \, rad\, s ^{-1}$ . Then

• A. the voltage leads the current by $45^{\circ}$
• B. the current leads the voltage by $45^{\circ}$
• C. the current leads the voltage by $60^{\circ}$
• D. the voltage leads the current by $60^{\circ}$

Answer 1

Answer: (B)

the current leads the voltage by $45^{\circ}$

Answer 2

$R=5 \Omega, C=1mF, \omega=200\,rad\,s^{-1}$
As it is pure $RC$ circuit
$\therefore$ Current leads the voltage
by phase angle $\phi$ given by
$tan \,\phi=\frac{X_{c}}{R}=\frac{1}{\omega CR}$
$=\frac{1}{200\times1\times10^{-3}\times5}=1$
$\therefore \phi=tan^{-1} \left(1\right)$
$=45^{\circ}$