Physics Question: Self-Inductance

Question:

What is the unit of self-inductance?

Explanation

Self-inductance is the property of a coil that causes it to oppose any change in the current flowing through it by producing a self-induced electromotive force (EMF).

Definition of Self-Inductance

Self-inductance \( L \) is defined as the ratio of the induced EMF \( E \) to the rate of change of current \( \frac{di}{dt} \).

Formula:

\[ L = \frac{E}{\frac{di}{dt}} \]

Rearranged form (Induced EMF):

\[ E = -L \frac{di}{dt} \]

Where:

Unit of Self-Inductance

From the formula:

\[ L = \frac{\text{Volt}}{\text{Ampere/second}} = \frac{\text{Volt} \cdot \text{second}}{\text{Ampere}} \]

This derived unit is known as the Henry (H).

Other Units for Comparison