Practice question

Given: A circular loop of radius 0.13 m with 20 turns carries a current of 3.5 A . What is the magnetic field at the nter? ( μ_0 = 4 π × 10⁻⁷ T m/A ) These values define the system as per NCERT data. Formula: Magnetic field B = μ_0 N I/2 R. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: B = frac4 π × 10⁻⁷ × 20 × 3.52 × 0.13 = frac28 π × 10⁻⁶⁰.26 = 1.0769 π × 10⁻⁴ approx 3.38 × 10⁻⁴ T . Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.