A solenoid of length 22.5 cm has a total of 900 turns and carries a current of 0.8 A. What is the magnetising field H near the centre and far away from the ends of the solenoid ?

Explanation

`l = 22.5 cm = 22.5 xx 10^(-2) m = (45)/(2) xx 10^(-2)m`
`N = 900, I = 0.8A, H = ?`
`H = (NI)/(l) = (900 xx 0.8)/((45)/(2)xx10^(-2))`
`H = (900)/(45) xx 0.8 xx 10^(2) xx 2`
`:. H = 3200 Am^(-1)`.