Question

The equation of an alternating current is $I=50\sqrt{2}sin\left(400\pi t\right)$A, then the frequency and the root mean square value of the current respectively are

• A. $200Hz,50A$
• B. $400Hz$, $50\sqrt{2}A$
• C. $200Hz$, $50\sqrt{2}A$
• D. $500Hz,200A$

Answer 1

The correct option is A $200Hz,50A$

$i=50\sqrt{2}sin\left(400\pi t\right)A$

$=i_{max}sin\left(wt\right)A$

So, $w=400\pi$

$2\pi f=400\pi$

$f=200Hz$

$i_{max}=50\sqrt{2}$

$i_{rms}=\frac{i_{max}}{\sqrt{2}}$

$=\frac{50\sqrt{2}}{\sqrt{2}}$

$=50A$