1Which of these has the same dimensions as electric charge?
Electric charge and elementary charge both have the dimensions [T A].
ElectrostaticsClass 12, Electric Charges and Fields
Dimensional formula of Electric charge
[T A]
Current times time, from I = Q/t. In SI the ampere is the base quantity, so charge carries the extra time.
How to get the dimensional formula of electric charge
- Start from the definition: electric charge = electric current × time.
- Put in the dimension of each part: [A] × [T].
- Add the powers of each base quantity: [T A].
Quantities with the dimensions [T A]
Equal dimensions do not make them the same quantity. Compare electric charge with the others in the full grid.
Three questions on electric charge
2What is the SI unit of electric charge?
The SI unit of electric charge is the coulomb (C).
3Do electric charge and volume charge density have the same dimensions?
Electric charge is [T A] but volume charge density is [L⁻³ T A].
An equation that uses electric charge
Equation checker
Matching dimensions are necessary, not sufficient. A check cannot see pure numbers such as 1/2 or 2π, so a consistent equation can still be wrong.
Read as
F = q v B sin(θ)F[M L T-2]=q v B sin(theta)[M L T-2]Dimensionally consistentEvery term is [M L T-2]
v = velocityθ = angle
Electric charge: quick answers
What is the dimensional formula of electric charge?
The dimensional formula of electric charge is [T A]. It comes from electric charge = electric current × time.
What is the SI unit of electric charge?
The SI unit of electric charge is the coulomb (C).
Which quantities have the same dimensions as electric charge?
Electric charge shares [T A] with elementary charge. Equal dimensions do not make them the same quantity.