Practice question

Given: A solenoid with 1000 turns per meter and current 2 A has a core with relative permeability μ_r = 200 . What is the magnetic field B inside? These values define the system as per NCERT data. Formula: Magnetic field B = μ_0 μ_r H, where H = n I. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Given: n = 1000 m^{-1, I = 2 A, μ_r = 200, μ_0 = 4π × 10⁻⁷ T m A^{-1 . First, H = 1000 × 2 = 2000 A m^{-1 . Then, B = 4π × 10⁻⁷ × 200 × 2000 = 0.5024 T approx 0.5 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.