A Rowland ring of mean radius 15 cm has 3500 turns of wire wound on a ferromagnetic core of relative permeability 800. What is the magnetic field B in the core for a magnetising current of 1.2 A?

A toroid has core (non-ferromagnetic ) of inner radius 25 cm and outer radius 26 cm, around which 3500 turns of a wire are wound. If the current in the wire is 11 A, what is the magnetic field (i) outside the toroid , (ii) inside the core of the toroid, and (iii)in the empty space surrounded by the toroid.

A solenoid of length 0.5 m has a radius of 1 cm and is made up of 500 turns. It carries a current of 5 A. What is the magnitude of magnetic field inside the solenoid ?

If a thin wire of length 88 cm is bent into a circular loop and a current of 1A is passed, a. What is the magnetic field at the centre? b. What is the magnetic field at the centre if the wire is bent into a semicircle and doubled on it? c. If the wire is looped into two loops, find the magnetic field at the centre.

6.A straight wire carrying a current of 12 A is bent into a semi-circular arc of radius 2.0 cm as shown in Fig. (a). Consider the magnetic field B at the centre of the arc. a . What is the magnetic field due to the straight segments? b. In what way the contribution to B from the semicircle differs from that of a circular loop and in what way does it resemble? c. Would your answer be different if the wire were bent into a semi-circular arc of the same radius but in the opposite way as shown in Fig. (b)?

A circular coil of radius 1*5 cm carries a current of 1*5A . If the coil has 25 turns , find the magnetic field .What is the value of M ?

A 50 turn circular coil of radius 2.0 cm carrying a current of 5.0 A is rotated in a magnetic field of strength 0.20 T. (a) What is the maximum torque that acts on the coil? (b) in a particular position of the coil, the torque acting on it is half of this maximum. What is the angle between the magnetic field and the plane of the coil?

A solenoid of length 10 cm and radius 1 cm contains 200 turns and carries a current of 10 A. Find the magnetic field at a point on the axis at a distance of 10cm from the centre.

A long solenoid is fabricated by closely winding a wire of radius 0.5 mm over a cylindrical nonmagnetic frame so that the successive turns nearly touch each other. What would be the magnetic field B at the centre of the solenoid if it carries a current of 5 A?