What is the magnitude of axial field due to a bar magnet of length 3 cm at a distance of 75 cm from its mid-point if its magnetic moment is 0.6 Am?

Options

A. 0.013`mu` T
B. 0.113 `mu` T
C. 0.213 `mu` T
D. 0.313 `mu` T

Answer

C

Explanation

Here, `m`= 0.6 A `m^(2)`, `r`=75 cm = 0.75 m
`B_("axial")=(mu_(0))/(4pi)*((2m)/(r^(3)))=10^(-7)xx(2xx0.6)/((0.75)^(3))`
`therefore" "B_("axial")=2.13xx10^(-7)` T = 0.213`mu`T.