Electromagnetic Effects
Muhtasari
Move a magnet near a coil of wire and a voltage springs up out of nowhere; send a current through a wire and it becomes wrapped in a magnetic field; place that wire in another magnet's field and it is pushed sideways. Electricity and magnetism are two sides of one coin, and this link runs every generator, motor, relay and loudspeaker.
In this topic you will learn how a changing magnetic field induces an e.m.f., what affects its size and direction, the magnetic field patterns around wires and solenoids, and how a simple a.c. generator works. You will also relate the directions of force, field and current, and see the magnetic effect of a current applied in relays and loudspeakers.
Malengo
- Know that a conductor moving across a magnetic field or a changing magnetic field linking with a conductor can induce an e.m.f. in the conductor
- Describe an experiment to demonstrate electromagnetic induction
- State the factors affecting the magnitude of an induced e.m.f.
- Describe the pattern and direction of the magnetic field due to currents in straight wires and in solenoids
- Describe an experiment to identify the pattern of the magnetic field (including direction) due to currents in straight wires and in solenoids
- Describe how the magnetic effect of a current is used in relays and loudspeakers and give examples of their application
- [Supplement] Know that the direction of an induced e.m.f. opposes the change causing it
- [Supplement] State and use the relative directions of force, field and induced current
- [Supplement] Describe a simple form of a.c. generator (rotating coil or rotating magnet) and the use of slip rings and brushes where needed
- [Supplement] Sketch and interpret graphs of e.m.f. against time for simple a.c. generators and relate the position of the generator coil to the peaks, troughs and zeros of the e.m.f.
- [Supplement] State the qualitative variation of the strength of the magnetic field around straight wires and solenoids
- [Supplement] Describe the effect on the magnetic field around straight wires and solenoids of changing the magnitude and direction of the current
Maelezo ya Somo
Inapatikana kwenye programu ya Green Bridge
Pakua programu ya Green Bridge CBT kwenye simu yako au kompyuta yako ili kupata maelezo kamili ya masomo, maswali ya mazoezi, na mengi zaidi.
Tathmini ya Somo
Hongera kwa kukamilisha somo la Electromagnetic Effects. Sasa kwa kuwa umechunguza dhana na mawazo muhimu, ni wakati wa kuweka ujuzi wako kwa mtihani. Sehemu hii inatoa mazoezi mbalimbali maswali yaliyoundwa ili kuimarisha uelewaji wako na kukusaidia kupima ufahamu wako wa nyenzo.
Utakutana na mchanganyiko wa aina mbalimbali za maswali, ikiwemo maswali ya kuchagua jibu sahihi, maswali ya majibu mafupi, na maswali ya insha. Kila swali limebuniwa kwa umakini ili kupima vipengele tofauti vya maarifa yako na ujuzi wa kufikiri kwa makini.
Tumia sehemu hii ya tathmini kama fursa ya kuimarisha uelewa wako wa mada na kubaini maeneo yoyote ambapo unaweza kuhitaji kusoma zaidi. Usikatishwe tamaa na changamoto zozote utakazokutana nazo; badala yake, zitazame kama fursa za kukua na kuboresha.
- An e.m.f. is induced in a coil when: A. a magnet rests inside it B. the magnetic field through it changes C. it is painted black D. it is at a high temperature Answer: B
- Which change does NOT increase the e.m.f. induced in a coil? A. moving the magnet faster B. using more turns C. using a stronger magnet D. holding the magnet still Answer: D
- The magnetic field around a long straight current-carrying wire is: A. straight lines along the wire B. concentric circles around the wire C. a uniform field D. zero Answer: B
- In a simple a.c. generator the induced e.m.f. is greatest when the coil is: A. vertical B. horizontal C. at rest D. removed Answer: B
- The force on a current-carrying wire in a magnetic field is found using: A. the right-hand grip rule B. Fleming's right-hand rule C. Fleming's left-hand rule D. Ohm's law Answer: C
Inapatikana kwenye programu ya Green Bridge
Pakua programu ya Green Bridge CBT kwenye simu yako au kompyuta yako ili kupata maelezo kamili ya masomo, maswali ya mazoezi, na mengi zaidi.
Inapatikana kwenye programu ya Green Bridge
Pakua programu ya Green Bridge CBT kwenye simu yako au kompyuta yako ili kupata maelezo kamili ya masomo, maswali ya mazoezi, na mengi zaidi.
Vitabu Vinavyopendekezwa
Fanya Mazoezi ya Maswali ya Majaribio
Ungependa kufanya mazoezi ya maswali ya majaribio kuhusu Electromagnetic Effects? Pakua programu ya Green Bridge CBT ili kupata maswali ya majaribio na tathmini kamili za mazoezi kuhusu mada hii.
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