There is a magnetic material of coericivty `2 xx 10^3 Am^-1`. What current should flow through a solenoid of length 15 cm havign 150 turns to demagnetise the substance completely?

The number density of electron in copper is 8.5 xx10^(28)m^(-3) . Find the current flowing through a copper wire of length 20 cm, area of cross section 1 mm square,when connected to a battery of 3 V. Given the electron mobility = 4.5xx10^(-6)m^(2)V^(-1) s^(-1) and electron charge = 1.6 xx 10^(-19)C.

A solenoid of length 50cm, having 100 turns carries a current of 2.5A. Find the magnetic field at one end of the solenoid.

A bar magnet has coercivity 4xx10^(3) Am^(-1) it is desired to demagnetize it by inserting it inside a solenoid 12cm long and has 60 turns the current that should be sent through the solenoid.

A solenoid of length 50cm, having 100 turns carries a current of 2.5A. Find the magnetic field in the interior of the solenoid.

A closely wound solenoid of 2000 turns and area of cross-section 1.6 xx 10^1 m^2 . carrying a current of 4.0 A, is suspended through its centre allowing it to turn in a horizontal plane. What is the magnetic moment associated with the solenoid?

A closely wound solenoid of 800 turns and area of cross section 2.5 xx 10^-4 m^2 carries a current of 3.0 A. Explain the sense in which the solenoid acts like a bar magnet. What is its associated magnetic moment?