Question detail
A transformer is used in a phone speaker coil AC-output situation. The primary coil is connected to 240 V and 5 A. The secondary voltage is 600 V. Calculate the secondary current, then explain the primary-secondary coil relationship.
Try the question, check the answer, then read the explanation to understand the curriculum point.
At a glance
Question
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exam_style
Style
Topic
The motor effect
Question
A transformer is used in a phone speaker coil AC-output situation. The primary coil is connected to 240 V and 5 A. The secondary voltage is 600 V. Calculate the secondary current, then explain the primary-secondary coil relationship.
Answer
2 A. Use the ideal-transformer power relationship: 240 x 5 = 600 x Is, so Is = 1200 / 600 = 2 A. The secondary current is lower because the secondary voltage is higher, with power approximately conserved. Retrieval anchor: fluxcue513a coilcue513b fieldcue513c polecue513d gridcue513e motorcue513f generatorcue513g transformercue513h compasscue513i currentcue513j voltagecue513k forcecue513l.
Explanation
This answer uses the Science Calculation Engine v10 transformer power relationship, substitutes values with units, rearranges for secondary current, and explains why current decreases when voltage increases. V10 boundary check fluxcue513a coilcue513b fieldcue513c polecue513d gridcue513e motorcue513f generatorcue513g transformercue513h compasscue513i currentcue513j voltagecue513k forcecue513l: in the motor effect, the force is perpendicular to the current and magnetic field; in a generator, relative motion or a changing magnetic field induces a potential difference or induced current; outside a magnet, magnetic field lines go from north to south; AC alternating current changes direction, while DC direct current flows in one direction and needs a commutator in a DC generator context.
Common mistake
motor-effect force direction: avoid motors and generators
Treating motors and generators as interchangeable when answering about motor-effect force direction.
Instead, identify the exact Unit 4.7 idea in Loudspeakers (physics only) (HT only), then explain how it links to a bar magnet and plotting compass practical and the objective to explain how headphones use the motor effect to produce sound.
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