AIIMS 2018 Physics Magnetic Field in Solenoids MCQ Question

To find the magnetic field $B$ inside a solenoid, we use the formula $B = \mu_0 \cdot n \cdot I$, where $\mu_0 = 4\pi \times 10^{-7} \, \text{T m/A}$ is the permeability of free space, $n$ is the number of turns per unit length, and $I$ is the current. For this solenoid, $n = \frac{600 \, \text{turns}}{0.6 \, \text{m}} = 1000 \, \text{turns/m}$ and $I = 4 \, \text{A}$, leading to $B = 4\pi \times 10^{-7} \cdot 1000 \cdot 4 \approx 5.024 \times 10^{-3} \, \text{T}$. The other options are incorrect as they do not match this calculated value, demonstrating a misunderstanding of the solenoid's magnetic field properties.