Electromagnetic Effects (continued)
Akopọ
Send a current through a wire that sits in a magnetic field and the wire is pushed sideways. Wind that wire into a coil and the push becomes a spin: this is how every electric motor turns. Pair two coils on an iron core and a changing current in one induces a voltage in the other, which is how transformers raise and lower the voltages that power the world.
In this lesson you will describe the force on a current-carrying conductor and how reversing the current or field reverses it, find force directions and deflect charged particles, explain the turning effect on a coil and the d.c. motor with its commutator, and work through transformers from construction to the turns equation, the efficiency equation, and why high-voltage transmission cuts the power lost as \(I^2R\) heating in cables.
Awọn Afojusun
- Describe an experiment to show that a force acts on a current-carrying conductor in a magnetic field, including the effect of reversing: (a) the current (b) the direction of the field
- Know that a current-carrying coil in a magnetic field may experience a turning effect and that the turning effect is increased by increasing: (a) the number of turns on the coil (b) the current (c) the strength of the magnetic field
- Describe the construction of a simple transformer with a soft-iron core, as used for voltage transformations
- Use the terms primary, secondary, step-up and step-down
- Recall and use the equation Vₚ / Vₛ = Nₚ / Nₛ where p and s refer to primary and secondary
- Describe the use of transformers in high- voltage transmission of electricity
- State the advantages of high-voltage transmission
- [Supplement] Recall and use the relative directions of force, magnetic field and current
- [Supplement] Determine the direction of the force on beams of charged particles in a magnetic field
- [Supplement] Describe the operation of an electric motor, including the action of a split-ring commutator and brushes
- [Supplement] Explain the principle of operation of a simple iron-cored transformer
- [Supplement] Recall and use the equation for 100% efficiency in a transformer I V = I V p p s s where p and s refer to primary and secondary
- [Supplement] Recall and use the equation P = I2R to explain why power losses in cables are smaller when the voltage is greater
Ẹ̀kọ́ Ohùn
Gbọ́ ẹ̀kọ́ yìí nínú áàpù
Àwòrán ọpọlọ
A ti ṣe àwòrán kókó yìí kí o lè rí bí àwọn èrò ṣe so pọ̀.
Ṣí àwòrán ọpọlọ nínú áàpù
Káàdì ìrántí
Ìdánrawò kíákíá lórí ohun tí wọ́n ń dán wò nínú kókó yìí.
Ṣe ìdánrawò káàdì wọ̀nyí nínú áàpù
Akọ̀wé Ẹ̀kọ́
Àkọsílẹ̀ Ẹ̀kọ́ Pípé wà lórí Ohun Èlò Green Bridge
Gba ohun èlò Green Bridge CBT sórí fóònù tàbí kọ̀mpútà rẹ fún gbogbo ilé ìkàwé IGCSE: ìwé ìdánwò àtijọ́, ìlànà ìdíwọ̀n, àwòrán èrò, káàdì ìkẹ́kọ̀ọ́ àti ẹ̀kọ́ ohùn.
Ìdánwò Ẹ̀kọ́
Oriire fun ipari ẹkọ lori Electromagnetic Effects (continued). Ni bayi ti o ti ṣawari naa awọn imọran bọtini ati awọn imọran, o to akoko lati fi imọ rẹ si idanwo. Ẹka yii nfunni ni ọpọlọpọ awọn adaṣe awọn ibeere ti a ṣe lati fun oye rẹ lokun ati ṣe iranlọwọ fun ọ lati ṣe iwọn oye ohun elo naa.
Iwọ yoo pade adalu awọn iru ibeere, pẹlu awọn ibeere olumulo pupọ, awọn ibeere idahun kukuru, ati awọn ibeere iwe kikọ. Gbogbo ibeere kọọkan ni a ṣe pẹlu iṣaro lati ṣe ayẹwo awọn ẹya oriṣiriṣi ti imọ rẹ ati awọn ogbon ironu pataki.
Lo ise abala yii gege bi anfaani lati mu oye re lori koko-ọrọ naa lagbara ati lati ṣe idanimọ eyikeyi agbegbe ti o le nilo afikun ikẹkọ. Maṣe jẹ ki awọn italaya eyikeyi ti o ba pade da ọ lójú; dipo, wo wọn gẹgẹ bi awọn anfaani fun idagbasoke ati ilọsiwaju.
- The force on a current-carrying wire in a magnetic field is reversed by A. increasing the current B. reversing the current direction C. using a longer wire D. switching off the current Answer: B
- Fleming's left-hand rule gives the direction of the A. magnetic field B. induced current C. force on the wire D. e.m.f. Answer: C
- A transformer with 200 primary turns and 50 secondary turns is a A. step-up transformer B. step-down transformer C. d.c. transformer D. rectifier Answer: B
- A transformer has Vp = 240 V, Vs = 12 V and Np = 1000 turns. Ns equals A. 20 B. 50 C. 200 D. 2000 Answer: B
- Electricity is transmitted at high voltage mainly to A. increase the current B. reduce the power lost as heat in the cables C. change a.c. to d.c. D. raise the resistance of the cables Answer: B
Ṣiṣẹ́ lórí àwọn ìbéèrè wọ̀nyí nínú ohun èlò náà
Ṣiṣẹ́ lórí àwọn ìbéèrè wọ̀nyí nínú ohun èlò náà
Awọn Iwe Itọsọna Ti a Gba Nimọran
Ẹ̀kọ́ síwájú láti àwọn orísun ṣíṣí
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Abala ìwé ẹ̀kọ́
Motors, Generators, and Transformers
Explain how electric motors, generators, and transformers work
"Physics: Motors, Generators, and Transformers" by OpenStax, OpenStax, Rice University, licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Source: https://openstax.org/books/physics/pages/20-2-motors-generators-and-transformers. Access for free at https://openstax.org/books/physics/pages/1-introduction
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Abala ìwé ẹ̀kọ́
Magnetic Fields, Field Lines, and Force
Summarize properties of magnets and describe how some nonmagnetic materials can become magnetized
"Physics: Magnetic Fields, Field Lines, and Force" by OpenStax, OpenStax, Rice University, licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Source: https://openstax.org/books/physics/pages/20-1-magnetic-fields-field-lines-and-force. Access for free at https://openstax.org/books/physics/pages/1-introduction
Àwọn àjọ mìíràn ló tẹ̀ wọ́n jáde lábẹ́ ìwé àṣẹ ṣíṣí, a sì dá wọn lọ́lá bí wọ́n ṣe béèrè. Àwọn ìjápọ̀ ń ṣí ojú òpó wọn.
Ṣe Adaṣe Awọn Ibeere Idanwo Adaṣe
Ṣe o fẹ ṣe adaṣe awọn ibeere idanwo adaṣe nipa Electromagnetic Effects (continued)? Ṣe igbasilẹ ohun elo Green Bridge CBT lati wọle si awọn ibeere idanwo adaṣe ati awọn ayẹwo adaṣe kikun fun koko-ọrọ yii.
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