ئېلکترومەغناطىسلىق تەڭشەتكۈن

Electromagnetism ji bo bêtayîn-ê li ser hejmarên fizîkî yên ku di navbera pargrên bi baranîn de derbasên fizîkî da. Derbasên electromagnetik hatine têne bi sahên electromagnetic yên ku ji elektrik û magnetik sahên ve têne yêbûn, û ew ê wekariyek e ku çavkaniyên electromagnetic an jî xweşka werin.

Kî dîsa Electromagnetism?

Di salan 1820 de, fizîkan danmard Hans Christian Oersted, dîsa ku kompasê di nav conductor ê ke bi baranîn de derketina, dike deflected. Di dema ku derketina vegerandin, kompasê bi posisyonê xweya girêdayî wergirt. Ew dîsa muhîman dersazî derbasên electricity û magnetism, ku wekheviye bi elektromagnet û bi hêza zanistanên ku modern industry piramend in.

Oersted dîsa ku sah magnetik nekêş ne ya conductor ê ke elektronan di raya, herçî conductor ê tehati lê zîn ne, ji ber ku conductor ê ji copper nonmagnetic ve hatine în. Elektronan di wire de çavkirina, sah magnetik bi conductor hatine yêbûn. Ji ber ku sah magnetik bi pargrên bi baranîn re hatine yêbûn, hêza derketina zêdetir, û sah magnetik zêdetir. Fig. 1 sah magnetik bi conductor ê ke derketina hatine şînîn. Dîwar conductor ê series ê concentric circles ê sahê, ku ji ber ku hemî líneyan were şînin, dikare be şînimandî cylinder ê belaşîn circles ê sah bi conductor.

Fig. 1 - Sah magnetik form kirin di nav conductor ê ke derketina hatine.

Her dema ku derketina di conductor de ye, líneyan ê force di nav conductor de. [Figure 10-26] Ji ber ku hêza derketina zêdetir, líneyan ê force di circle A de hatine çavkirin. Ji ber ku hêza derketina zêdetir, líneyan ê force di circle B de hatine çavkirin, û ji ber ku hêza derketina zêdetir, líneyan ê force di circle C de hatine çavkirin. Ji ber ku líneyan ê force (circle) guherandin ji circle A bi B, líneyan ê force nû di circle A de hatine çavkirin. Ji ber ku hêza derketina zêdetir, líneyan ê force zêdetir, û líneyan ê force di circle C de hatine çavkirin.

Fig. 2 - Expansion of magnetic field as current increases.

Ji ber ku hêza derketina direct current e, sah magnetik stationary yê. Ji ber ku hêza derketina vegerandin, sah magnetik collapse û magnetism di nav conductor de vegerandin.

Compass needle bi karîna ku direction ê sah magnetik di nav conductor ê ke derketina hatine şînîn. Fig. 3 View A compass needle bi posisyonê perpendicular û approximately one inch from, a current carrying conductor. Ji ber ku hêza derketina na, end ê north seeking ê compass needle bi pole ê earth's magnetic hatine şînîn. Ji ber ku hêza derketina hatine, needle lines itself up bi perpendicular radius drawn from the conductor. Ji ber ku compass needle small magnet e, bi líneyan ê force extending from south to north inside the metal, it will turn until the direction of these lines agrees with the direction of the lines of force around the conductor. As the compass needle is moved around the conductor, it will maintain itself in a position at right angles to the conductor, indicating that the magnetic field around a current carrying conductor is circular. As shown in View B of Figure 3, when the direction of current flow through the conductor is reversed, the compass needle will point in the opposite direction, indicating the magnetic field has reversed its direction.

Fig.3 - Magnetic field around a current-carrying conductor.

A method used to determine the direction of the lines of force when the direction of the current flow is known, is shown in Figure 4. If the conductor is grasped in the left hand, with the thumb pointing in the direction of current flow, the fingers will be wrapped around the conductor in the same direction as the lines of the magnetic field. This is called the left-hand rule.