Question

The force acting on a pole of pole strength $1Am$ is ${10}^{-4}N$ . The magnetic field at that point is:

• A. $\text{11 }\times \text{ 1}{\text{0}}^{\text{-4}}\text{T}$
• B. $\text{10 }\times \text{ 1}{\text{0}}^{\text{-4}}\text{T}$
• C. $\text{0}\text{.1 }\times \text{ 1}{\text{0}}^{\text{-4}}\text{T}$
• D. $\text{1 }\times \text{ 1}{\text{0}}^{\text{-4}}\text{T}$

Answer 1

Answer: (D)

A magnetic charge (pole) placed in a magnetic field experiences a force
$F=mB$
Here, $F={10}^{-4}N,m=1Am$
$\therefore$ $B=\frac{F}{m}=\frac{{10}^{-4}}{1}={10}^{-4}T$
Note: The force on positive magnetic charge is along the field and a force on a, negative magnetic charge is opposite to the field.