- Exam
- JEE Main
- Year
- 2020
- Date
- 5 September
- Shift
- Evening Shift
- Subject
- Physics
- Chapter
- Units and Dimensions
JEE Main 2020 · 5 September · Evening Shift · Physics · Units and Dimensions
The quantities x = 1 μ _ 0 ∈ _ 0 , y = (E)/(B) and z = (l)/(CR) are...
Options
- Ax, y and z have the same dimension.
- BOnly x and z have the same dimension
- COnly x and y have the same dimension
- DOnly y and z have the same dimension.
Correct answer
A. x, y and z have the same dimension.
Step-by-step solution
(a) Dimensions of quantity are given bellow
Now the dimension of is given by
\left[x\right] = \dfrac{1}{\left[\sqrt{{\mu}_{0}{\in}_{0}}\right]} = \sqrt{\dfrac{1}{\left[N{C}^{- 2}{s}^{2}\right]\left[{C}^{2}{N}^{- 1}{m}^{- 2}\right]}}\left[x\right] = m{s}^{- 1}B = \left[T\right] = \left[Wb{m}^{- 2}\right] = \left[Vs{m}^{- 2}\right]E = \left[V{m}^{- 1}\right]y
(c) The dimension of capacitance and resistance is given by,
Now the dimension of is given by
\left[z\right] = \dfrac{\left[l\right]}{\left[CR\right]} = \dfrac{\left[m\right]}{\left[C{V}^{- 1}\right]\left[V{C}^{- 1}s\right]} = m{s}^{- 1}
All quantities are having the dimensions of velocity.