Fill in the following blanks which suitable words :
(a) The lines of ......round a straight current-carrying conductor are in the shape of .........
(b) For a current-carrying solenoid, the magnetic field is like that of a ..........
(c) The magnetic effect of a coil can be increased by increasing the number of ........, increasing the ................., or inserting an ................. core.
(d) If a coil is viewed from one end and the current flows in an anticlockwise direction, then this end is a .......... pole.
(e) If a coil is viewed from one end, and the current flows in a clockwise direction,then this end is a ...... pole.

Explanation

(a) magnetic field , concentric circles (b) bar magnet (c ) turns , current , iron (d) north (e) south