1Which of these has the same dimensions as stopping potential?
Stopping potential and electromotive force (emf) both have the dimensions [M L² T⁻³ A⁻¹].
Modern physicsClass 12, Dual Nature of Radiation and Matter
Dimensional formula of Stopping potential
[M L2 T-3 A-1]
The potential that just stops the fastest photoelectrons, kinetic energy over charge.
How to get the dimensional formula of stopping potential
- Start from the definition: stopping potential = energy / electric charge.
- velocity = length / time, so velocity is [L] / [T] = [L T-1].
- energy = mass × velocity2, so energy is [M] × [L T-1]2 = [M L2 T-2].
- electric charge = electric current × time, so electric charge is [A] × [T] = [T A].
- Put in the dimension of each part: [M L2 T-2] / [T A].
- Add the powers of each base quantity: [M L2 T-3 A-1].
Quantities with the dimensions [M L² T⁻³ A⁻¹]
Equal dimensions do not make them the same quantity. Compare stopping potential with the others in the full grid.
Three questions on stopping potential
2What is the SI unit of stopping potential?
The SI unit of stopping potential is the volt (V).
3Which one has different dimensions from the others?
Decay constant is [T⁻¹]. The other three are all [M L² T⁻³ A⁻¹].
Stopping potential: quick answers
What is the dimensional formula of stopping potential?
The dimensional formula of stopping potential is [M L² T⁻³ A⁻¹]. It comes from stopping potential = energy / electric charge.
What is the SI unit of stopping potential?
The SI unit of stopping potential is the volt (V).
Which quantities have the same dimensions as stopping potential?
Stopping potential shares [M L² T⁻³ A⁻¹] with electric potential, potential difference, electromotive force (emf). Equal dimensions do not make them the same quantity.