Physics is far from the easiest subject, especially for those who have problems with the exact sciences. It is 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 consider how to determine the direction of electromagnetic force using a hand using the well-known rule of the left hand.
This rule makes it a little easier if not understanding the laws, then at least solving problems. True, it can only be applied by someone who is even a little versed in physics and its terms. Many textbooks contain an image that clearly explains how to apply the left hand rule in solving problems. Physics, however, is clearly not the kind of science where you often have to put your hand to visual models, so develop your imagination.
First you need to find out the direction of the current in that part of the circuit where you are going to apply the rule of the left hand. Remember that an error in determining the direction will show you the exact opposite direction of the electromagnetic force, which will automatically negate all your further efforts and calculations. As soon as you determine the direction of the current, position the left palm so that the fingers indicate this course.
Next, you need to find the direction of the magnetic induction vector . If you have any problems with this, you should refresh your knowledge with the help of textbooks. When you find the desired vector, turn the palm so that this vector fits into the open palm of the same left hand. The whole difficulty of applying the rule of the left hand lies precisely in whether you can correctly apply your knowledge to find constant vectors.
When you are sure that your palm is positioned properly, pull the thumb so that its position is perpendicular to the direction of the current (where the rest of the fingers of the bunch are pointing). Remember that the finger is far from the most accurate indicator in physics, and in this case shows only an approximate direction. If you are interested in accuracy, then after applying the rule of the left hand, use the 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 accurate calculations - it can only serve to quickly determine the direction of electromagnetic force. In addition, its use requires additional conditions of the problem, and therefore it is not always applicable in practice.
Naturally, it is not always possible to have a hand in the object being studied, because sometimes it does not exist at all (in theoretical problems). In this case, in addition to imagination, other methods should be applied. 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 lines with signatures - it will be easier to figure it out later.