Magnetic field — this force field which is created by moving electric charge and affects it. Power characteristic of magnetic field is a vector of induction of magnetic field. In tasks often it is required to determine the direction of a vector of magnetic induction by physics.
It is required to you
- - magnet;
- - magnetic needle;
- - gimlet.
Instruction
1. Define the direction of a vector of induction in the field of a permanent magnet. In the beginning find northern and southern poles in a magnet — northern it is usually painted in blue color and marked with Latin letter N, and southern paint in red and put letter S. If there are no paint and marks on a magnet, define poles by a magnetic needle with the known poles.
2. Establish an arrow near a magnet that one of the ends of an arrow was attracted to it. If to a magnet the South Pole of an arrow was attracted, then on a magnet it is the North Pole. If, on the contrary, it was attracted northern, then on a magnet it corresponds to the South Pole. Then use the simple rule which is that power lines of magnetic field (vector of magnetic induction) leave the North Pole of a magnet and are included into southern.
3. Define the direction of a vector of magnetic induction in the direct conductor. In the beginning connect the direct conductor to a current source. Do not forget that it is necessary to take the direction from a positive pole of a source of current to negative for the direction of current. Take the right gimlet (corkscrew) or present that you hold it in the hand.
4. Twist a corkscrew in the direction of the movement of current in the conductor. Thus rotation of the handle will specify the direction of power lines of magnetic field. Sketch lines and construct a vector on a tangent. The constructed vector will also show the direction of magnetic induction.
5. Learn where the induction vector in a round with current is directed. Also take a corkscrew (gimlet). Establish it perpendicular to the plane of this round. Rotate the gimlet in the direction of the movement of current. Progress of a corkscrew also defines the direction of lines of magnetic induction in the center of a round.
6. Define the direction of magnetic field for the coil and the solenoid (coil of the conductor which is reeled up on a cylindrical surface). Use the rule of the right hand. Connect the coil/solenoid to any source of current, having received the complete closed chain. The right hand arrange so that four extended fingers specified the direction of current in rounds.
7. The set aside thumb will show the direction of a vector of magnetic induction in the solenoid or the coil. Not to use the rule of the right hand if it seemed to you difficult, bring a magnetic needle to the solenoid or the coil. The blue (northern) end of an arrow will specify the direction of a vector of induction. Pay attention that power lines in the solenoid are straight lines.