Find the magnetic field at point P in figure. The curved portion is a semicircle connected to two long straight wires. Image
Options

Question

Find the magnetic field at point P in figure. The curved portion is a semicircle connected to two long straight wires. Image

G1 Physics · Accepted Answer

Field at the centre due to the semicircle is B(arc)=μ₀I/(4r). The relevant straight-wire contribution is μ₀I/(4πr). Their directions are the same. Therefore B = μ₀I/(4r) + μ₀I/(4πr) = μ₀I/(2r)[1/2 + 1/(2π)].