Question

(a) Use the Ampere's law to show that the strength of the magnetic field inside an ideal cylindrical solenoid (a coil) is given off by

B = µ(0)ni

where n is the revolution density (the number of revolutions per unit length of the solenoid) and i is the current through the solenoid. (3p)

The current in the solenoid increases at a constant rate to a constant value I in a certain time t.
(b) Draw a figure across the cross section of the coil, from which it can be seen how the current, the electric field and the magnetic field are directed in the coil (i) as the current increases and (ii) after the current reaches the constant value I. (3p)

Answer 1

Ler s asSe Hat Solenoid has got 'Ni tun and Solemoid enclosed - N At eno

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