Electromagnetic Effects Continued
Gbogbo ọrọ náà
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.
Ebumnobi
- 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
Akọmọ Ojú-ẹkọ
Ọ dị na ngwa Green Bridge
Budata ngwa Green Bridge CBT na ekwentị maọbụ kọmputa gị iji nweta akwụkwọ ndụmọdụ zuru oke, ajụjụ mmụta, na ndị ọzọ.
Ayẹwo Ẹkọ
Ekele diri gi maka imecha ihe karịrị na Electromagnetic Effects Continued. 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.
- 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
Ọ dị na ngwa Green Bridge
Budata ngwa Green Bridge CBT na ekwentị maọbụ kọmputa gị iji nweta akwụkwọ ndụmọdụ zuru oke, ajụjụ mmụta, na ndị ọzọ.
Ọ dị na ngwa Green Bridge
Budata ngwa Green Bridge CBT na ekwentị maọbụ kọmputa gị iji nweta akwụkwọ ndụmọdụ zuru oke, ajụjụ mmụta, na ndị ọzọ.
Àwọn Ìwé Tó Dáa Láti Kà
Meecha Ajụjụ Ule Ọmarịcha
Ị chọrọ ime ajụjụ ule ọmarịcha gbasara Electromagnetic Effects Continued? Budata ngwa Green Bridge CBT iji nweta ajụjụ ule ọmarịcha na nyocha zuru ezu gbasara isiokwu a.
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