Question

Draw a bar magnet and indicate the poles

Answer 1

d= volume of the oil drop/ area of the film

 

= 4/3 *pi* (0.025cm)^3/(pi* (10 cm)^2

 

= 2.08X10^-7 cm

Answer 2

Figure :-

$\huge\fcolorbox{red}{red}{ \: \: \: N \: \: \: }\fcolorbox{blue}{blue}{ \: \: \: S \: \: \: }$

Explaination :-

What is bar magnet ?

➜ A bar magnet is a rectangular piece of an object, made up of iron, steel or any other ferromagnetic substance or ferromagnetic composite, that shows permanent magnetic properties. It has two poles, a north and a south pole such that when suspended freely, the magnet aligns itself so that the northern pole points towards the magnetic north pole of the earth.

Types of Bar Magnet

➜ There are two types of bar magnet:

Cylindrical bar magnet: A cylindrical rod is also known as rod magnets that have a thickness equal to larger than the diameter enabling high magnetism property. These bar magnets find application in educational, experimental, and research uses.

Rectangular bar magnet: Rectangular bar magnets find applications in manufacturing and engineering industries as they have magnetic strength and field greater than the other magnets

Uses of bar magnet.

➜ The main function of bar magnets is to to pick up small metallic objects like metal shavings or nails and screws, as magnetic stirring rods in laboratory applications, and as magnets on refrigerators. Their most common application is the needle used in compasses.

• Bar magnets are used as stirrers in laboratory for magnetic experiments.
• They also find applications in medical procedures.
• Electronic devices such as telephones, radios, and television sets use magnets.
• Many industries use bar magnets for the collection of loose metals and also for retaining magnetism of other magnets.