Question

The most effective method of magnetization is___________.
A) Single touch method
B) Double touch method
C) Electrical method
D) All the above.

Answer 1

Hint: Ferromagnetic substances are widely used in several applications. We know that a ferromagnetic substance placed in an external magnetic field is strongly magnetized in the direction of the applied external magnetic field.

Complete step by step answer:
Single touch method: Iron bar is rubbed with a magnet repeatedly. Then that process is called magnetization of the iron bar by the single-touch method. This method is the simplest and also the most convenient method to make a small magnet that does not require a large magnetic field of attraction. The only thing you need is a ferromagnetic object and a permanent magnet.
Double Touch Method: This method is very similar to the single touch method. Here, two permanent magnets are taken to magnetize the ferromagnetic material, operating in opposite directions.
Electrical method: A ferromagnetic material is placed inside a solenoid and a direct current is passed into a solenoid (along insulated wire coiled into a cylinder) and it produces a strong magnetic field inside the coil which is uniform in strength and direction. For example, a steel bar placed inside the current-carrying coil or solenoid for a short time interval becomes magnetized due to magnetic induction from the solenoid. Magnetization by electrical method produces more powerful magnets than other magnetization methods.

$\therefore $ The electrical method is the most effective method of magnetization because it is much quicker than the other methods and produces strong magnets. The correct option is option (C).

Note:
The substances which retain their ferromagnetic property at room temperature for a long time are called permanent magnets. The electromagnets or temporary magnets are made from the soft ferromagnetic substance that can be demagnetized by removing the electric current. Single touch and double touch methods take more time to get magnetized and are also less effective.