JEE Main 201511 AprilOnline
- Exam
- JEE Main
- Year
- 2015
- Date
- 11 April
- Mode
- Online
- Subject
- Physics
- Chapter
- Units and Dimensions
JEE Main 2015 · 11 April · Online · Physics · Units and Dimensions
If electronic charge e , electron mass m , speed of light in vacuum...
If electronic charge , electron mass , speed of light in vacuum and Planck's constant are taken as fundamental quantities, the permeability of vacuum can be expressed in units of:
Options
- A
- B
- C
- D
Correct answer
D.
Step-by-step solution
Magnetic potential energy inside a solenoid is
Where self-inductor
number of turns per unit length
Dimensionally, \left[U\right] = \left[\dfrac{hc}{\lambda}\right]
\left[A\right] = {\left[l\right]}^{2}
\left[{\mu}_{0}\right] = \left[\dfrac{hc}{\lambda}\right]\dfrac{[ l ]}{\left[{l}^{2}\right]}\dfrac{\left[{t}^{2}\right]}{{\left[e\right]}^{2}}= \left[\dfrac{h}{\lambda}\dfrac{t}{{e}^{2}}\right] = \left[\dfrac{h}{c{e}^{2}}\right]{\mu}_{0} = \dfrac{h}{c{e}^{2}}
Where self-inductor
number of turns per unit length
Dimensionally, \left[U\right] = \left[\dfrac{hc}{\lambda}\right]
\left[A\right] = {\left[l\right]}^{2}
\left[{\mu}_{0}\right] = \left[\dfrac{hc}{\lambda}\right]\dfrac{[ l ]}{\left[{l}^{2}\right]}\dfrac{\left[{t}^{2}\right]}{{\left[e\right]}^{2}}= \left[\dfrac{h}{\lambda}\dfrac{t}{{e}^{2}}\right] = \left[\dfrac{h}{c{e}^{2}}\right]{\mu}_{0} = \dfrac{h}{c{e}^{2}}