Physics is not the easiest subject, especially for those who have problems with the exact sciences. It's no secret that not everyone gets along with sign systems, there are people who need to touch or at least see what they are studying. Fortunately, in addition to formulas and boring books, there are visual ways. For example, in this article, we will look at how to determine the direction of an electromagnetic force with the help of a hand, using the well-known left hand rule.
This rule makes it a little easier, if not understanding the laws, then at least solving problems. True, only those who are at least a little versed in physics and its terms can apply it. Many textbooks have an image that explains very clearly how to use the left hand rule when solving problems. Physics, however, is clearly not the kind of science where you often have to put your hand on visual models, so develop your imagination.
First you need to know the direction of current flow in the part of the circuit where you are going to apply the left hand rule. Remember that a mistake in determining the direction will show you the opposite direction of the electromagnetic force, which will automatically nullify all your further efforts and calculations. As soon as you determine the direction of the current, place your left palm so that your fingers indicate this course.
Next, you need to find the direction of the magnetic induction vector. If you have any problems with this, it is worth brushing up your knowledge with the help of textbooks. When you find the desired vector, turn your palm so that this vector enters the open palm of the same left hand. The tricky part of applying the left hand rule lies precisely in whether you can apply your knowledge correctly to find constant vectors.
When you are sure that your palm is properly positioned, pull back your thumb so that its position becomes perpendicular to the direction of the current (where the other fingers of the bunch are pointing). Remember that a finger is far from the most accurate indicator in physics, and in this case it only shows an approximate direction. If you are interested in accuracy, then after applying the left hand rule, use a protractor to bring the angle between the direction of the current and the direction indicated by the thumb to 90 degrees.
It should be remembered that the rule in question is not suitable for precise calculations - it can only serve to quickly determine the direction of the electromagnetic force. In addition, its use requires additional conditions of the problem, andtherefore not always applicable in practice.
Naturally, it is not always possible to have a hand in the object under study, because sometimes it does not exist at all (in theoretical problems). In this case, in addition to imagination, other methods should be used. For example, you can draw a diagram on paper and apply the left hand rule to the drawing. The hand itself can also be schematically depicted in the figure for greater clarity. The main thing is not to get confused in the vectors, otherwise you can make mistakes. Therefore, do not forget to mark all the lines with signatures - it will be easier for you to figure it out later.
