Question

A periodic voltage waveform observed in an oscilloscope across load is shown below. A moving iron (MI) meter connected across the same load reads_______volts(Answer upto 2 decimal pleaces).

• A. 8.41
• B. 0.841
• C. 10
• D. 84.1

Answer 1

The correct option is A 8.41

$\text{RMS value of triangular wave}$
$=\frac{V_m}{\sqrt{3}}$

$\text{RMS value of sinusoidal wave}$
$=\frac{V_m}{\sqrt{2}}$

$\text{RMS value of square wave}$
$=V_m$


$\text{RMS of waveform}$

$=\sqrt{{\left(\frac{10}{\sqrt{3}}\right)}^2\times \frac{T_1}{T}+{\left(\frac{10}{\sqrt{2}}\right)}^2\times \frac{T_2}{T}+(10{)}^2\times \frac{T_3}{T}+(10{)}^2\times \frac{T_4}{T}}$


$=\sqrt{\frac{100}{3}\times \frac{2.5}{10}+\frac{100}{2}\times \frac{2.5}{10}+100\times \frac{1}{10}+100\times \frac{4}{10}}=8.416V$