Picture of coil of wire for physics practicals

The magnetic field (B) inside a long solenoid is given by:
B = μ₀ × (N/L) × I

Where:
μ₀ is the permeability of free space (a constant, 4π × 10⁻⁷ T·m/A)
N is the number of turns in the coil
L is the length of the coil
I is the current flowing through the coil

From the image, I can see:

• Number of turns (N) = 200 turns
• Length of the coil (L) = 0.10 m
• Current (I) = 2.0 A

B = (4π × 10⁻⁷ T·m/A) × (200 turns / 0.10 m) × 2.0 A

B = (4π × 10⁻⁷) × (2000 m⁻¹) × 2.0 A
B = (4π × 10⁻⁷) × 4000 T
B = 16000π × 10⁻⁷ T
B = 1.6π × 10⁻³ T
B ≈ 5.03 × 10⁻³ T

The magnetic field inside the solenoid is approximately 5.03 × 10⁻³ Tesla.