The Motor Effect
Gbogbo ọrọ náà
Stop reading for a moment and count the electric motors within ten metres of you. The fan in a laptop. The buzz in a phone. The pump in a fridge, the drum of a washing machine, the passenger window of a car, the disc that spins a hard drive, the wipers, the fuel pump. A family car carries more than thirty and almost nobody could name five. Every one runs on a single idea small enough to fit in a sentence: put a current through a wire that is already sitting in a magnetic field, and something shoves the wire sideways.
This lesson is about that shove. You will find out where it comes from, why it acts sideways to both the current and the field rather than along either, and why the magnet gets shoved just as hard the other way. You will learn to read a force direction straight off an arrangement with nothing but your own left hand, a skill the specification names outright. Then you will bend the wire into a loop and watch a push turn into a spin, which is the whole of an electric motor in one step. One thing has to be said before any of it: on this course every single statement of this topic is printed in bold type, which means the whole of it is Extension Tier material. The next section explains exactly what that does and does not mean for you.
Ebumnobi
- A current carrying conductor has a magnetic field around the wire. When a current carrying conductor is placed in a magnetic field so that it cuts lines of magnetic force, the magnet and the conductor exert a force on each other. This is called the motor effect. The conductor will not experience a force if it is parallel to the magnetic field.
- The size of the force can be increased by: increasing the strength of the magnetic field; increasing the size of the current; increasing the length of the conductor in the magnetic field.
- The direction of the force is reversed if either the direction of the current or the direction of the magnetic field is reversed. Students should be able to identify the direction of the force using Flemings left-hand rule.
- A coil of wire carrying a current in a magnetic field tends to rotate. This is the basis of an electric motor.
Maapụ uche
E seela isiokwu a ka ị hụ otu echiche si ejikọta.
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Akwụkwọ Ọmụmụ
Ndetu Nkuzi Zuru Ezu di na Ngwa Green Bridge
Nweta ngwa Green Bridge CBT na ekwenti gi ma o bu kompiuta maka ulo akwukwo IGCSE zuru oke: akwukwo ule ndi gara aga, usoro nyocha, eserese uche, kaadi omumu na nkuzi olu.
Nnyocha Ọmụmụ
Ekele diri gi maka imecha ihe karịrị na The Motor Effect. Ugbu a na ị na-enyochakwa isi echiche na echiche ndị dị mkpa, ọ bụ oge iji nwalee ihe ị ma. Ngwa a na-enye ụdị ajụjụ ọmụmụ dị iche iche emebere iji kwado nghọta gị wee nyere gị aka ịmata otú ị ghọtara ihe ndị a kụziri.
Ị ga-ahụ ngwakọta nke ụdị ajụjụ dị iche iche, gụnyere ajụjụ chọrọ ịhọrọ otu n’ime ọtụtụ azịza, ajụjụ chọrọ mkpirisi azịza, na ajụjụ ede ede. A na-arụpụta ajụjụ ọ bụla nke ọma iji nwalee akụkụ dị iche iche nke ihe ọmụma gị na nkà nke ịtụgharị uche.
Jiri akụkụ a nke nyocha ka ohere iji kụziere ihe ị matara banyere isiokwu ahụ ma chọpụta ebe ọ bụla ị nwere ike ịchọ ọmụmụ ihe ọzọ. Ekwela ka nsogbu ọ bụla ị na-eche ihu mee ka ị daa mba; kama, lee ha anya dị ka ohere maka ịzụlite onwe gị na imeziwanye.
- In Fleming's left-hand rule, what does the first finger point along? A. The direction of the force on the conductor B. The direction of the magnetic field C. The direction of the conventional current D. The direction of the flow of electrons Answer: B
- A straight wire lies between the poles of a magnet, parallel to the magnetic field lines. A large current is passed through the wire. What force acts on the wire? A. No force at all B. A force at right angles to the field C. A force along the direction of the current D. A force twice the size of the force when the wire is at right angles to the field Answer: A
- Which change would NOT increase the size of the force on a current-carrying wire in a magnetic field? A. Using a stronger magnetic field B. Increasing the current in the wire C. Increasing the length of the wire that lies inside the field D. Turning the wire so that it lies along the magnetic field lines Answer: D
- The current in a wire in a magnetic field is reversed, and the magnet is also turned round so that its poles trade places. What happens to the direction of the force on the wire? A. It is reversed B. It is unchanged C. It becomes zero D. It turns through 90 degrees Answer: B
- Why does a rectangular coil carrying a current in a magnetic field tend to rotate? A. Its two long sides carry current in opposite directions, so they are pushed in opposite directions on opposite sides of the axle B. Its two long sides carry current in the same direction, so they are pushed the same way C. The magnet is attracted to the coil D. The coil becomes an induced magnet and is attracted to the pole faces Answer: A
Rue ajuju ndi a n'ime ngwa ahu
Rue ajuju ndi a n'ime ngwa ahu
Akwụkwọ A Na-atụ Aro
Meecha Ajụjụ Ule Ọmarịcha
Ị chọrọ ime ajụjụ ule ọmarịcha gbasara The Motor Effect? Budata ngwa Green Bridge CBT iji nweta ajụjụ ule ọmarịcha na nyocha zuru ezu gbasara isiokwu a.
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