The SI unit of inductance, H (the henry), is equal to the following: (Hint: use the fact that the back emf produced by an inductor is given by emf = L * di/dt) 0 V-A/s; 0 V-s; Vlm; V-s/A.
The Correct Answer and Explanation is:
Correct Answer:
V·s/A (volt-second per ampere)
Explanation:
The SI unit of inductance is called the henry (H). To understand what 1 henry is in terms of base units, we use the definition of inductance and the relationship between electromotive force (emf), inductance, and the rate of change of current.
The relationship is given by: emf=L⋅didt\text{emf} = L \cdot \frac{di}{dt}emf=L⋅dtdi
Where:
- emf is the electromotive force in volts (V)
- L is inductance in henrys (H)
- didt\frac{di}{dt}dtdi is the rate of change of current in amperes per second (A/s)
Now, solve for L: L=emfdidt=VA/s=V\cdotps/AL = \frac{\text{emf}}{\frac{di}{dt}} = \frac{\text{V}}{\text{A/s}} = \text{V·s/A}L=dtdiemf=A/sV=V\cdotps/A
So, 1 henry is the inductance of a circuit in which an emf of 1 volt is produced when the current changes at a rate of 1 ampere per second. This makes the unit of inductance: 1 H=1 V\cdotps/A1\ \text{H} = 1\ \text{V·s/A}1 H=1 V\cdotps/A
This means the henry can be understood as the amount of inductance that results in a back emf of 1 volt when the current through the coil changes at a rate of 1 ampere per second.
This definition links electrical properties (volts and amperes) with time (seconds), showing how inductance relates to the dynamic behavior of electric circuits. It emphasizes the role of inductors in resisting changes in current and inducing a voltage in response to that change.
Other options, such as “0 V-A/s,” “0 V-s,” and “Vlm” are either dimensionally incorrect or not valid SI units. Therefore, the only correct and meaningful expression of the henry in base units is: V\cdotps/A\boxed{\text{V·s/A}}V\cdotps/A
