The length of solenoid is 0.1 m and it's diameter is very small. A wir...
Theoretical Background:
A solenoid is a long coil of wires that produces a magnetic field when an electric current flows through it. The magnetic field inside a solenoid is uniform and can be calculated using the formula:
B = μ₀ * (n * I)
Where:
B is the magnetic field strength,
μ₀ is the permeability of free space (4π × 10^-7 T·m/A),
n is the number of turns per unit length,
I is the current flowing through the solenoid.
To calculate the magnetic field at the middle of the solenoid, we need to determine the number of turns and the current in the inner and outer layers separately.
Given Data:
Length of solenoid (l) = 0.1 m
Number of turns in the inner layer (n₁) = 50
Number of turns in the outer layer (n₂) = 40
Current in the solenoid (I) = 3 A
Calculations:
Number of turns per unit length in the inner layer:n₁ = n₁_total / l
Where n₁_total is the total number of turns in the inner layer.
n₁ = 50 / 0.1
n₁ = 500 turns/m
Number of turns per unit length in the outer layer:n₂ = n₂_total / l
Where n₂_total is the total number of turns in the outer layer.
n₂ = 40 / 0.1
n₂ = 400 turns/m
Magnetic field inside the solenoid:Using the formula mentioned earlier:
B₁ = μ₀ * (n₁ * I)
B₂ = μ₀ * (n₂ * I)
Since the currents in the inner and outer layers are flowing in opposite directions, the net magnetic field at the middle of the solenoid is the difference between the magnetic fields of the two layers.
B = B₁ - B₂
Substituting the values:
B = μ₀ * (n₁ * I) - μ₀ * (n₂ * I)
B = μ₀ * I * (n₁ - n₂)
Final Answer:B = 4π × 10^-7 T·m/A * 3 A * (500 - 400)
B = 12π × 10^-5 T
Therefore, the magnetic field at the middle of the solenoid is 12π × 10^-5 T.