A solenoid of 1200 turns is wound uniformly in a single layer on a glass tube 2 m long and 0.2 m in diameter. The magnetic intensity at the center of the solenoid when a current of 2 A flows through it is:

Find the magnetic intensity at the centre of a solenoid with 1200 turns, length 2 m, diameter 0.2 m, carrying a current of 2 A.

Calculate the number of turns per unit length.

$$n = \frac{N}{L} = \frac{1200}{2} = 600 \text{ turns/m}$$

Apply the formula for magnetic intensity (H).

The magnetic intensity (magnetic field strength H) inside a solenoid is:

$$H = nI = 600 \times 2 = 1200 \text{ A m}^{-1} = 1.2 \times 10^3 \text{ A m}^{-1}$$

Note: The diameter of the solenoid does not affect the magnetic intensity H inside it.

The correct answer is $$1.2 \times 10^3$$ A m$$^{-1}$$.