The magnet induction at a point 1 Ã… away from a proton measured along its axis of spin is (magnetic moment of the proton is `1.4xx10^(-26)"A m"^(2)`)

Options

A. 0.28 mT
B. 28 mT
C. 0.028 mT
D. 2.8 mT

Answer

D

Explanation

On the axis of a magnetic dipoles, magnetic induction is
`B=(mu_(0))/(4pi)xx(2m)/(r^(3))`
Here, `r=1 Ã…= 10^(-10)" m", m= 1.4xx10^(-26)"A m"^(-2)` and
`(mu)/(4pi)=10^(-7)"N A"^(-2)`
`therefore" "B=(10^(-7)xx2xx1.4xx10^(-26))/((10^(-10))^(3))=(10^(-7)xx2.8xx10^(-26))/(10^(-30))`
`" "=2.8xx10^(-3)` T = 2.8 mT