Question: What is the magnetic field due to a circular loop of radius R carrying current I at a point on its axis at a distance x from the center?

Options:

1. μ₀I/(2R)
2. μ₀I/(2(x² + R²)^(3/2))
3. μ₀I/(4πR)
4. μ₀I/(x² + R²)

Correct Answer: μ₀I/(2(x² + R²)^(3/2))

Solution:

The magnetic field at a point on the axis of a circular loop at a distance x from the center is given by B = μ₀I/(2(x² + R²)^(3/2)).