Question detail

A transformer is used in a power-station transformer diagnosis 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

Type

exam_style

Style

Topic

Induced potential, transformers and the National Grid (physics only) (HT only)

Question

A transformer is used in a power-station transformer diagnosis 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: fluxcue827a coilcue827b fieldcue827c polecue827d gridcue827e motorcue827f generatorcue827g transformercue827h compasscue827i currentcue827j voltagecue827k forcecue827l.

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 fluxcue827a coilcue827b fieldcue827c polecue827d gridcue827e motorcue827f generatorcue827g transformercue827h compasscue827i currentcue827j voltagecue827k forcecue827l: 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

National Grid transformer reasoning: avoid magnetic field...

Treating magnetic field direction and force direction as interchangeable when answering about National Grid transformer reasoning.

Instead, identify the exact Unit 4.7 idea in Transformers (HT only), then explain how it links to a calculation using primary and secondary coils and the objective to apply MS 3b and MS 3c when using transformer equations.

Related flashcards

Flashcard 1 of 5

Press Space to flip, arrows to move

Related practice questions

Question 1 of 5

Choose an answer, get feedback, then move sideways through the set.

0 of 5 attempted
exam Q1: 3c when using transformer… | Induced potential,… | ExamCompanion