Question 109: Magnetism and Matter

Question

Two short bar magnets of length $$1$$ $$cm$$ each have magnetic moments $$1.20$$ $$A{m^2}$$  and $$1.00$$ $$A{m^2}$$ respectively. They are placed on a horizontal table parallel to each other with their $$N$$ poles pointing towards the South. They have a common magnetic equator and are separated by a distance of $$20.0$$ $$cm.$$  The value of the resultant horizontal magnetic induction at the mid-point $$O$$ of the line joining their centres is close to $$\left( \, ight.$$ Horizontal component of earth's magnetic induction is $$3.6 	imes 10.5Wb/{m^2})$$

Accepted Answer

Given: $${M_1} = 1.20A{m^2}\,\,\,$$ and $$\,\,\,{M_2} = 1.00A{m^2}$$
$$r = {{20} \over 2}cm = 0.1m$$
$${B_{net}} = {B_1} + {B_2} + {B_H}$$
$${B_{net}} = {{{\mu _0}\left( {{M_1} + {M_2}} ight)} \over {{r^3}}} + {B_H}$$
$$ = {{{{10}^{ - 7}}\left( {1.2 + 1} ight)} \over {{{\left( {0.1} ight)}^3}}} + 3.6 	imes {10^{ - 5}}$$
$$ = 2.56 	imes {10^{ - 4}}\,\,wb/{m^2}$$

Answer

$$3.6 	imes 10.5\,\,Wb/{m^2}$$

Answer

$$2.56 	imes 10.4\,\,Wb/{m^2}$$

Answer

$$3.50 	imes 10.4\,\,Wb/{m^2}$$

Answer

$$5.80 	imes 10.4\,Wb/{m^2}$$

Magnetism and Matter

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