Question

The SI unit of the inductance, the henry can by written as

• A. weber/ampere
• B. volt-second/ampere
• C. joule/( ampere$)^2$
• D. ohm-second

Answer 1

Answer: (D)

ohm-second

Answer 2

$(a) \, L = \frac{ \phi}{ i }$ or henry $= \frac{\text{ weber} }{\text{ ampere} }$ (b) e = - L $\bigg ( \frac{ di}{ dt} \bigg)$ $\therefore L = - \frac{ e}{ ( di / dt ) }$ or henry $= \frac{ \text{volt - second}}{ \text{ampere}}$ (c) U = $\frac{1}{2} Li^2 \therefore L = \frac{ 2 U}{ i^2 }$ or henry $= \frac{\text{ joule}}{\text{ (ampere)}^2 }$ (d) U = $\frac{1}{2} Li^2 = i^2 R t$ $\therefore$ L = Rt or henry = ohm-second