The polarity of a magnet can also be determined using the clock rule (also known as the final rule of magnetism). Couples that occur counterclockwise are positive couples. Alternatively, couples that occur clockwise are negative couples. So what happens when your hand points in or out of the paper? Couples pointing outward from the paper should be analyzed as positive couples, while couples pointing inward should be analyzed as negative couples. A form of legal rule is used in situations where an ordered operation must be performed on two vectors a and b, the result of which is a vector c perpendicular to a and b. The most common example is the cross vector product. The rule of law applies the following procedure to select one of the two directions. The right handle ruler is used to determine the relationship between current and magnetic field as a function of the direction of rotation. To understand the definition, one must understand the demonstration of the rule of good gripping. To do this, the wire should be held in the right hand and the thumb should point in the direction of the current flow and then wrap your fingers around the wire. Now the wavy fingers show the direction of the magnetic field around the wire and how the compass would align if placed at this point.
Understanding the concept of the right grip rule is difficult for many students and so they make stupid mistakes in exams, like using the left hand for the right grip rule. It should be noted that this rule should be performed only with the right hand. In addition to determining the relationship between current and magnetic field, he also shows that moving charges can generate magnetic fields. A conventional current consists of moving loads of a positive nature. When a conventional current passes through a conductive wire, the wire is affected by a magnetic field that pushes it. We can use the right ruler to identify the direction of the force acting on the live wire. In this pattern, your fingers point in the direction of the magnetic field, your thumb points in the direction of the conventional current flowing through the wire, and your palm indicates the direction in which the wire is being pushed (force). When choosing three vectors that should be perpendicular to each other, there are two different solutions, so when expressing this idea in mathematics, ambiguity as to the intended solution must be eliminated. André-Marie Ampère, a French physicist and mathematician who gave his name to the rule, was inspired by Hans Christian Ørsted, another physicist who experimented with magnetic needles.
Ørsted observed that the needles swirled near a live wire and concluded that electricity could generate magnetic fields. The rule on the right states that: To determine the direction of the magnetic force towards a positive moving charge, point your right thumb in the direction of the velocity (v), your index finger in the direction of the magnetic field (B), and your middle finger point in the direction of the resulting magnetic force (F). Negative charges are affected by a force in the opposite direction. One of the best ways to help students become familiar with the right hand rule is to give a visual demonstration that will help them identify and correct their misconceptions about orthogonal relationships and coordinate systems. The exchange of labels on two axes reverses the hand. Reversing the direction of one (or all three axes) also reverses the hand. (If the axes have no positive or negative direction, maneuverability is meaningless.) The inverse of two axes corresponds to a rotation of 180° about the remaining axis.  The following will help you remember that you are using your right hand and not your left hand: In mathematics and physics, the right-handed ruler is a common mnemonic for understanding 3-dimensional vector notation conventions. It was built at the end of the 19th century. It was invented by British physicist John Ambrose Fleming for use in electromagnetism. The correct ruler is used to determine the direction of magnetic field lines and current around a straight voltage conductor, magnet or coil inductor. For right-handed coordinates, the right thumb points along the z-axis in the positive direction and the curvature of the fingers represents the movement of the first or x-axis to the second or y-axis.