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: (A), (B), (C), (D)

(a) $L=\frac{\varphi }{i}$
or henry $=\frac{\text{ weber }}{\text{ ampere }}$
(b) $e=-L\left(\frac{di}{dt}\right)$
$\therefore L=-\frac{e}{(di/dt)}$
or henry $=\frac{\text{ volt }-\text{ second }}{\text{ ampere }}$
(c) $U=\frac{1}{2}L{i}^2$
$\therefore L=\frac{2U}{i^2}$
or henry $=\frac{\text{ joule }}{(\text{ ampere }{)}^2}$
(d) $U=\frac{1}{2}L{i}^2=i^{2}Rt$
$\therefore L=Rt$
or henry $=$ ohm-second