JEE Main2013PhysicsUnits and DimensionsActual
From the following, the quantity (constructed from the basic constants of nature), that has the dimensions, as well as correct order of magnitude, vis-a-vis typical atomic size, is:
Options
- Ae^2 4 ₀ m c^2
- B4 ₀ e^2 m e^2
- Cm e^2 4 ₀ b^2
- D4 ₀ m c^2 e^2
Correct answer
A. e^2 4 ₀ m c^2
Step-by-step solution
As E = mc ^2 also E = F s = kq q r ^2 r Therefore dimensionally aligned & mc ^2= 1 4 ₀ q ^2 r & r = e ^2 4 ₀ mc ^2 aligned