Question 133: Magnetism and Matter

Question

The horizontal component of earth's magnetic field at a place is $$3.5 	imes 10^{-5} \mathrm{~T}$$. A very long straight conductor carrying current of $$\sqrt{2} \mathrm{~A}$$ in the direction from South east to North West is placed. The force per unit length experienced by the conductor is __________ $$	imes 10^{-6} \mathrm{~N} / \mathrm{m}$$.

Accepted Answer

$$\begin{aligned}
& B_H=3.5 	imes 10^{-5} T \
& F=i \ell B \sin 	heta, \quad \mathrm{i}=\sqrt{2} \mathrm{~A} \
& \frac{F}{\ell}=i B \sin 	heta=\sqrt{2} 	imes 3.5 	imes 10^{-5} 	imes \frac{1}{\sqrt{2}} \
& =35 	imes 10^{-6} \mathrm{~N} / \mathrm{m}
\end{aligned}$$

Magnetism and Matter

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