Question

The r.m.s voltage of the wave form shown is:

• A. $10V$
• B. $7V$
• C. $6.37V$
• D. $11V$

Answer 1

Answer: (A)

Short trick:
$V_{rms}=\sqrt{\frac{{\left(V_1\right)}^2+{\left(V_2\right)}^3+{\left(V_3\right)}^2}{\text{ Number of loops }}}$
$V_{rms}=\sqrt{\frac{(10{)}^2+(10{)}^2+(10{)}^2}{3}}$
$V_{rms}=\sqrt{\frac{300}{3}}=\sqrt{100}=10V$