Question 264: Magnetism and Matter

Question

Two long parallel wires $X$ and $Y$, separated by a distance of 6 cm , carry currents of 5 A and 4A, respectively, in opposite directions as shown in the figure. Magnitude of the resultant magnetic field at point P at a distance of 4 cm from wire Y is $x 	imes 10^{-5} \mathrm{~T}$. The value of $x$ is _________ . Take permeability of free space as $\mu_0=4 \pi 	imes 10^{-7}$ SI units.

Accepted Answer

$$\begin{aligned}
& B=\frac{\mu_0(5)}{2 \pi 	imes .01}-\frac{\mu_0 4}{2 \pi 	imes 0.04} \
& =-\frac{100 \mu_0}{4 \pi} \
& =-100 	imes 10^{-7} \
& =-1 	imes 10^{-5} \mathrm{~T}
\end{aligned}$$

Magnetism and Matter

Choose the correct answer: