Question

Which of the following physical quantities have the same dimensions ?

• A. Electric displacement $(\vec{D})$ and surface charge density
• B. Displacement current and electric field
• C. Current density and surface charge density
• D. Electric potential and energy

Answer 1

Answer: (A)

Electric displacement
$\vec{D}={ϵ}_0\vec{E}$
$[D]=\left[{ϵ}_{0}E\right]=\left[{ϵ}_0\frac{\sigma }{{ϵ}_0}\right]$
$[D]=[\sigma ]$
$\to$ Surface change density $=\sigma$.