Question

The value of Bohr magneton $\left({\mu }_B\right)$ is :

• A. $9.3\times {10}^{-24}A{m}^2$
• B. $9.3\times {10}^{-20}A{m}^2$
• C. $9.3\times {10}^{-16}A{m}^2$
• D. $9.3\times {10}^{-12}A{m}^2$

Answer 1

Answer: (A)

$9.3\times {10}^{-24}A{m}^2$

${\mu }_B=\frac{eh}{2m_e}$
e$=$electron charge
$=$ $1\cdot 6\times {10}^{-19}$
h$=$ reduced Planck's constant
$=$ $\frac{6\cdot 62\times {10}^{-34}}{2\pi }{m}^{2}kg/s$
$m_e=$ mass of electron
$=$ $9\cdot 1\times {10}^{-31}kg$
${\mu }_B$ $=$ $\frac{1\cdot 6\times {10}^{-19}\times 6\cdot 62\times {10}^{-34}}{2\times 2\pi \times 9\cdot 1\times {10}^{-31}}$
${\mu }_B$ $=$ $9\cdot 3\times {10}^{-24}$ $A{m}^2$