MCQ
Which of the following is not a dimensionless quantity?
- ARelative magnetic permeability $\left(\mu_{{r}}\right)$
- BPower factor
- ✓Permeability of free space $\left(\mu_{0}\right)$
- DQuality factor
✓
Answer
Correct option: C.
Permeability of free space $\left(\mu_{0}\right)$
c
$\left[\mu_{{}}\right]=1 \text { as } \mu_{{r}}=\frac{\mu}{\mu_{{m}}}$
$\left[\mu_{{}}\right]=1 \text { as } \mu_{{r}}=\frac{\mu}{\mu_{{m}}}$
[power factor $(\cos \phi)]=1$
$\mu_T{0}=\frac{{B}_{0}}{{H}}\left(\right.$ unit $\left.={NA}^{-2}\right)$ : Not dimensionless
$\left[\mu_{0}\right]=\left[{MLT}^{-2} {A}^{-2}\right]$
quality factor (Q) $=\frac{\text { Energystored }}{\text { Energy dissipated per cycle }}$
So $Q$ is unitless $\&$ dimensionless.
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