A solenoid of length 1.5 m and 4 cm diameter possesses 10 turns per cm. A current of 5A is flowing through it, the magnetic induction at axis inside the solenoid is

(μ0 = 4π × 10^-7 weber amp^-1 m^-1)

Calculation:
The magnetic field inside a solenoid is given by the formula:

B = μ₀ × n × I

Where:

• μ₀ = 4π × 10^-7 weber amp^-1 m^-1 (permeability of free space)
• n = number of turns per unit length = 10 turns per cm = 10 × 10² turns/m
• I = current passing through the solenoid = 5A

Now, substituting the values into the equation:

B = (4π × 10^-7) × (10 × 10²) × 5

B = 2π × 10^-5 tesla

The magnetic induction at the axis inside the solenoid is 2π × 10^-5 tesla.